DatePicker durch CalendarDatePicker ersetzen (Zeitraum-Datumsfelder)

Avalonias Spinner-DatePicker übernimmt Änderungen nur über einen separaten
Häkchen-Button im Flyout und verwirft sie sonst stillschweigend. Betrifft
alle verbliebenen Zeitraum-Datumsfelder mit diesem Muster.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -0,0 +1,24 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    container:
+      image: mcr.microsoft.com/dotnet/sdk:10.0
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Restore
+        run: dotnet restore LehrerApp.sln
+
+      - name: Build
+        run: dotnet build LehrerApp.sln --no-restore --configuration Release
+
+      - name: Test
+        run: dotnet test LehrerApp.sln --no-build --configuration Release --logger "console;verbosity=normal"

.vscode/launch.json

@@ -5,7 +5,7 @@
       "name": "Desktop App starten",
       "type": "coreclr",
       "request": "launch",
-      "preLaunchTask": "Desktop bauen",
+      "preLaunchTask": "TemplateDesigner bauen",
       "program": "${workspaceFolder}/LehrerApp.Desktop/bin/Debug/net10.0/LehrerApp.Desktop.dll",
       "args": [],
       "cwd": "${workspaceFolder}/LehrerApp.Desktop",
@@ -15,6 +15,20 @@
         "DOTNET_ENVIRONMENT": "Development"
       }
     },
+    {
+      "name": "TemplateDesigner App starten",
+      "type": "coreclr",
+      "request": "launch",
+      "preLaunchTask": "Desktop bauen",
+      "program": "${workspaceFolder}/LehrerApp.TemplateDesigner/bin/Debug/net10.0/LehrerApp.TemplateDesigner.dll",
+      "args": [],
+      "cwd": "${workspaceFolder}/LehrerApp.TemplateDesigner",
+      "stopAtEntry": false,
+      "console": "internalConsole",
+      "env": {
+        "DOTNET_ENVIRONMENT": "Development"
+      }
+    },
     {
       "name": "API Server starten",
       "type": "coreclr",

.vscode/tasks.json

@@ -27,6 +27,19 @@
       "problemMatcher": "$msCompile",
       "group": "build"
     },
+    {
+      "label": "TemplateDesigner bauen",
+      "command": "dotnet",
+      "type": "process",
+      "args": [
+        "build",
+        "${workspaceFolder}/LehrerApp.TemplateDesigner/LehrerApp.TemplateDesigner.csproj",
+        "--configuration", "Debug",
+        "--verbosity", "minimal"
+      ],
+      "problemMatcher": "$msCompile",
+      "group": "build"
+    },
     {
       "label": "Solution bauen",
       "command": "dotnet",

CLAUDE.md

@@ -60,12 +60,16 @@ The API can also run via `docker/docker-compose.yml` (reads `JWT_SECRET` from th
   orchestration, timer-driven), `SnapshotService`, `Crypto/SyncCrypto` (AES-256-GCM payload
   encryption — desktop events are encrypted at rest and in transit; Companion/WebApp events are
   plaintext, see `PlainSyncEvent` vs `SyncEvent`).
+- **LehrerApp.WebUntis** — direkter, serverunabhängiger WebUntis-Client für den Desktop. Hält die
+  persönliche JSON-RPC-Sitzung lokal und parst den Schülerreport lokal; WebUntis-Zugangsdaten und
+  personenbezogene Antworten dürfen nicht über `LehrerApp.Api` geleitet werden.
 - **LehrerApp.Api** — minimal ASP.NET Core server: JWT auth, an append-only `EventStore` plus
   `SnapshotStore`/`ReadableSnapshotStore` per device, mapped in `Endpoints/Endpoints.cs`. Sync is
   optional — Desktop only registers `SyncEngine`/`SnapshotService` in DI when a server URL is
   configured (`AppBootstrapper.LoadServerUrl`).
 - Each library has a matching `*.Tests` project (`LehrerApp.Tests` → Core, `LehrerApp.Data.Tests` →
   Data, `LehrerApp.Desktop.Tests` → Desktop, `LehrerApp.Sync.Tests` → Sync), all xUnit.
+  `LehrerApp.WebUntis.Tests` covers the direct WebUntis client and report parser.
 
 ### MVVM conventions (Desktop)
 

Directory.Build.props

@@ -4,7 +4,7 @@
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <LangVersion>latest</LangVersion>
-    <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <!-- CS8618: falsch-positiv durch [ObservableProperty] Source Generator -->
     <NoWarn>CS8618</NoWarn>
   </PropertyGroup>

Directory.Packages.props

@@ -17,9 +17,10 @@
     <!-- Datenbank -->
     <PackageVersion Include="LiteDB" Version="5.0.21" />
 
-    <!-- PDF-Erzeugung (11.3) - nur LehrerApp.Desktop: zieht SkiaSharp-Native-Binaries mit,
+    <!-- PDF-Erzeugung: Desktop-Exporte und die unabhängige Templating-Library. -->
-         die im Server-Image (LehrerApp.Api) nichts verloren haben. -->
     <PackageVersion Include="QuestPDF" Version="2025.7.0" />
+    <PackageVersion Include="PDFtoImage" Version="5.4.0" />
+    <PackageVersion Include="PdfPig" Version="0.1.13" />
 
     <!-- API -->
     <PackageVersion Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="10.0.0" />

LehrerApp.Api.Tests/DwdWeatherServiceTests.cs

@@ -39,6 +39,8 @@ public sealed class DwdWeatherServiceTests
                 <dwd:Forecast dwd:elementName="FF"><dwd:value>5</dwd:value></dwd:Forecast>
                 <dwd:Forecast dwd:elementName="FX1"><dwd:value>-</dwd:value></dwd:Forecast>
                 <dwd:Forecast dwd:elementName="RR1c"><dwd:value>1.25</dwd:value></dwd:Forecast>
+                <dwd:Forecast dwd:elementName="R101"><dwd:value>67.6</dwd:value></dwd:Forecast>
+                <dwd:Forecast dwd:elementName="SunD1"><dwd:value>1800</dwd:value></dwd:Forecast>
                 <dwd:Forecast dwd:elementName="Neff"><dwd:value>75</dwd:value></dwd:Forecast>
                 <dwd:Forecast dwd:elementName="ww"><dwd:value>61</dwd:value></dwd:Forecast>
               </kml:ExtendedData></kml:Placemark></kml:Document>
@@ -52,9 +54,34 @@ public sealed class DwdWeatherServiceTests
         Assert.Equal(18, hour.WindSpeedKmh);
         Assert.Null(hour.WindGustKmh);
         Assert.Equal(1.3, hour.PrecipitationMm);
+        Assert.Equal(68, hour.PrecipitationProbabilityPercent);
+        Assert.Equal(30, hour.SunshineDurationMinutes);
         Assert.Equal(61, hour.WeatherCode);
     }
 
+    [Fact]
+    public void ParseMosmix_LiefertMehrAlsDreiTageFuerFolgewoche()
+    {
+        var start = DateTime.UtcNow.AddHours(1);
+        var timeSteps = string.Join("", Enumerable.Range(0, 100)
+            .Select(i => $"<dwd:TimeStep>{start.AddHours(i):yyyy-MM-dd'T'HH:mm:ss'Z'}</dwd:TimeStep>"));
+        var values = string.Join(' ', Enumerable.Repeat("293.15", 100));
+        var kml = $$"""
+            <?xml version="1.0" encoding="UTF-8"?>
+            <kml:kml xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:dwd="https://opendata.dwd.de/weather/lib/pointforecast_dwd_extension_V1_0.xsd">
+              <kml:Document><kml:ExtendedData><dwd:ProductDefinition>
+                <dwd:ForecastTimeSteps>{{timeSteps}}</dwd:ForecastTimeSteps>
+              </dwd:ProductDefinition></kml:ExtendedData><kml:Placemark><kml:ExtendedData>
+                <dwd:Forecast dwd:elementName="TTT"><dwd:value>{{values}}</dwd:value></dwd:Forecast>
+              </kml:ExtendedData></kml:Placemark></kml:Document>
+            </kml:kml>
+            """;
+
+        var parsed = DwdWeatherService.ParseMosmix(Zip("forecast.kml", kml));
+
+        Assert.Equal(100, parsed.Hours.Count);
+    }
+
     [Fact]
     public void ParseCapArchive_OrdnetWarnpolygonGeografischZu()
     {

LehrerApp.Api/DwdWeatherService.cs

@@ -138,7 +138,9 @@ public sealed class DwdWeatherService(HttpClient http)
             ? series[i] : null;
         var hours = new List<WeatherForecastHour>();
         var earliest = DateTime.UtcNow.AddHours(-1);
-        for (var i = 0; i < times.Count && hours.Count < 72; i++)
+        // MOSMIX_L reicht bis +240 h. Die vollständige Spanne ist für die Unterrichtsplanung
+        // sinnvoll, weil das Wochenraster auch in die Folgewoche geblättert werden kann.
+        for (var i = 0; i < times.Count && hours.Count < 240; i++)
         {
             if (times[i] < earliest) continue;
             hours.Add(new WeatherForecastHour
@@ -148,6 +150,10 @@ public sealed class DwdWeatherService(HttpClient http)
                 WindSpeedKmh = Round(Value("FF", i) * 3.6, 1),
                 WindGustKmh = Round(Value("FX1", i) * 3.6, 1),
                 PrecipitationMm = Round(Value("RR1c", i), 1),
+                // Beide Zusatzwerte stammen aus derselben MOSMIX-L-Datei. R101 bezeichnet die
+                // Wahrscheinlichkeit für >0,1 mm in der letzten Stunde, SunD1 liegt in Sekunden vor.
+                PrecipitationProbabilityPercent = Round(Value("R101", i), 0),
+                SunshineDurationMinutes = Round(Value("SunD1", i) / 60, 0),
                 CloudCoverPercent = Round(Value("Neff", i), 0),
                 WeatherCode = Value("ww", i) is { } code ? (int)Math.Round(code) : null,
             });

LehrerApp.Api/Endpoints/Endpoints.cs

@@ -1,6 +1,7 @@
 using System.IdentityModel.Tokens.Jwt;
 using System.Security.Claims;
 using System.Text;
+using System.Globalization;
 using LehrerApp.Core.Models;
 using LehrerApp.Sync.Models;
 using Microsoft.AspNetCore.Mvc;

LehrerApp.Api/EventStore.cs

@@ -1,4 +1,5 @@
 using LiteDB;
+using LehrerApp.Sync;
 using LehrerApp.Sync.Models;
 
 namespace LehrerApp.Api;
@@ -67,7 +68,7 @@ public class EventStore(string dataPath) : IDisposable
     {
         var col    = GetCol(userId);
         var events = col.Find(e => e.ServerSeq > since && e.DeviceId != requestingDeviceId)
-            .OrderBy(e => e.ServerSeq).Take(500)
+            .OrderBy(e => e.ServerSeq).Take(SyncProtocol.PullBatchSize)
             .Select(e => new SyncEvent { EventId = e.EventId, DeviceId = e.DeviceId,
                 DeviceType = e.DeviceType, Timestamp = e.Timestamp,
                 SequenceNr = e.ServerSeq, EntityType = e.EntityType,

LehrerApp.Core/Interfaces/IRepositories.cs

@@ -136,6 +136,40 @@ public interface IUntisSnapshotRepository
     void Save(UntisSnapshotEntry entry);
     void Delete(Guid id);
 }
+/// Lokaler Cache der Fehlzeiten-Berichtszeilen fürs Klassenlehrer-Feature (siehe TODO.md) —
+/// bewusst nicht synchronisiert (siehe Implementierung), jedes Gerät ruft WebUntis selbst ab.
+public interface IUntisAbsenceCacheRepository
+{
+    List<UntisAbsenceCacheEntry> GetByClassAndRange(string className, int startDate, int endDate);
+    /// Löscht vorhandene Zeilen im Bereich und fügt die übergebenen neu ein — fürs "heiße" Fenster,
+    /// dessen Inhalt sich seit dem letzten Abruf geändert haben kann.
+    void ReplaceRange(string className, int startDate, int endDate, IEnumerable<UntisAbsenceCacheEntry> entries);
+    /// Fügt nur ein, ohne zu löschen — fürs Erweitern der als endgültig angenommenen "kalten" Historie.
+    void InsertRange(IEnumerable<UntisAbsenceCacheEntry> entries);
+}
+/// Lokaler Cache der Klassenbuch-Berichtszeilen anderer Lehrkräfte fürs Klassenlehrer-Feature —
+/// gleiches Muster wie <see cref="IUntisAbsenceCacheRepository"/>.
+public interface IUntisClassRegisterCacheRepository
+{
+    List<UntisClassRegisterCacheEntry> GetByClassAndRange(string className, int startDate, int endDate);
+    void ReplaceRange(string className, int startDate, int endDate, IEnumerable<UntisClassRegisterCacheEntry> entries);
+    void InsertRange(IEnumerable<UntisClassRegisterCacheEntry> entries);
+}
+/// Lokaler Cache der aktuellen Klassenliste (Roster) fürs Klassenlehrer-Feature — anders als
+/// Fehlzeiten/Klassenbuch keine Historie, deshalb kein ReplaceRange/InsertRange, sondern immer der
+/// komplette Ersatz des zuletzt bekannten Standes einer Klasse.
+public interface IUntisStudentRosterCacheRepository
+{
+    List<UntisStudentRosterCacheEntry> GetByClass(string className);
+    void ReplaceAll(string className, IEnumerable<UntisStudentRosterCacheEntry> entries);
+}
+/// Merkt sich je Klasse+Berichtsart, wann das heiße Fenster zuletzt aufgefrischt wurde und wie weit
+/// die kalte Historie bereits abgedeckt ist (siehe UntisReportCacheService).
+public interface IUntisCacheFetchStateRepository
+{
+    UntisCacheFetchState? Get(string className, UntisCacheKind kind);
+    void Save(UntisCacheFetchState state);
+}
 /// Vom Nutzer bestätigte Zuordnungen WebUntis-Wochenmuster → LearningGroup.
 public interface IUntisSlotMappingRepository
 {
@@ -191,6 +225,9 @@ public interface IParticipationSessionRepository
 {
     List<ParticipationSession> GetByGroup(Guid groupId);
     ParticipationSession? GetById(Guid id);
+    // Für Aggregationen über alle Gruppen (z.B. Dashboard-Fehlzeiten-Warnung), die sonst pro
+    // Eintrag einzeln GetById aufrufen müssten — ein Bulk-Laden vermeidet dieses N+1-Muster.
+    List<ParticipationSession> GetAll();
     void Save(ParticipationSession session);
     void Delete(Guid id);
 }

LehrerApp.Core/Models/Exam.cs

@@ -13,6 +13,12 @@ public class Exam
     public DateOnly? ReturnedAt { get; set; }
     public Niveau? Niveau { get; set; }
     public string? Notes { get; set; }
+    public DateOnly? ApprovalGrantedAt { get; set; }
+    public DateOnly? AnnouncedAt { get; set; }
+    /// Verknüpft Parallelklausuren (gleiche Arbeit, mehrere Kurse) für den Kurs-Umschalter
+    /// auf der Klausuren-Hauptseite — Id der "Ursprungs"-Klausur, gesetzt beim Duplizieren
+    /// (siehe ExamDialogViewModel.Save).
+    public Guid? SharedExamGroupId { get; set; }
     public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
     public DateTime UpdatedAt { get; set; } = DateTime.UtcNow;
 }

LehrerApp.Core/Models/LearningGroup.cs

@@ -20,6 +20,19 @@ public class LearningGroup
     /// deaktivierbar - blendet die Erinnerung "Ungeplante Stunden" im Dashboard für diese Gruppe aus.
     /// </summary>
     public bool RequiresLessonPlanning { get; set; } = true;
+    /// <summary>
+    /// WebUntis-interne Unterrichtsnummer (lsid) dieser Lerngruppe, Grundlage für den Abruf des
+    /// "Fehlzeiten pro Unterricht"-Berichts. Wird von WebUntis pro Schuljahr neu vergeben und muss
+    /// deshalb händisch je Lerngruppe/Schuljahr gepflegt werden - keine JSON-RPC-Methode liefert sie.
+    /// </summary>
+    public int? WebUntisLessonId { get; set; }
+    /// <summary>
+    /// Vorgängergruppe aus dem Hochstufen (<see cref="Services.GroupRolloverService"/>) —
+    /// ermöglicht einen Schuljahresvergleich (z.B. Klausurschnitt) über die Kette hinweg.
+    /// Wird ausschließlich beim Hochstufen automatisch gesetzt; vor Einführung dieses Felds
+    /// hochgestufte Gruppen bleiben unverknüpft (kein rückwirkendes Verknüpfen vorgesehen).
+    /// </summary>
+    public Guid? PreviousGroupId { get; set; }
     public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
     public DateTime UpdatedAt { get; set; } = DateTime.UtcNow;
 }

LehrerApp.Core/Models/Participation.cs

@@ -24,9 +24,26 @@ public class ParticipationEntry
     // Bleibt für bereits gespeicherte Daten erhalten. Neue Schreibvorgänge setzen beide Felder.
     public bool HomeworkMissing { get; set; }
     public AttendanceStatus? Attendance { get; set; }
+    // Strichliste im Sitzplan (Nutzer-Feedback): RaisedHandCount zählt jede beobachtete Meldung,
+    // CalledOnCount die Teilmenge davon, bei der der Schüler auch drangekommen ist —
+    // "drangekommen" ist immer auch eine Meldung und erhöht daher immer beide Zähler zugleich,
+    // nie CalledOnCount allein. Ergibt nebenbei eine Aufrufgerechtigkeits-Quote
+    // (CalledOnCount / RaisedHandCount) und schlägt die Quantitätsbewertung vor, siehe
+    // ParticipationCountSuggestion.
+    public int RaisedHandCount { get; set; }
+    public int CalledOnCount { get; set; }
+    /// <summary>
+    /// Tagesflagge (Nutzer-Feedback): markiert eine session-bezogene Bewertung als besonders
+    /// herausragend oder besonders schwach, unabhängig von der Richtung ("egal in welche
+    /// Richtung, herausragend festhalten"). Rein deskriptiv — fließt nirgends in eine Berechnung
+    /// (Mitarbeitsnote 3.2, Aufrufgerechtigkeit) ein, nur zur Erinnerung/Dokumentation.
+    /// </summary>
+    public DayHighlightKind? DayHighlight { get; set; }
     public DateTime UpdatedAt { get; set; } = DateTime.UtcNow;
 }
 
+public enum DayHighlightKind { Standout, Sleepy, Rough }
+
 /// <summary>
 /// Hausaufgabenstatus einer Sitzung; null bedeutet, dass für diesen Termin keine
 /// Hausaufgabe erfasst wurde. MissingOpen kann später in MissingOverdue oder SubmittedLate
@@ -160,3 +177,27 @@ public static class ParticipationRatingScale
         _ => value,
     };
 }
+
+/// <summary>
+/// Nutzer-Feedback: die Strichliste im Sitzplan (<see cref="ParticipationEntry.RaisedHandCount"/>)
+/// schlägt direkt eine Quantitätsbewertung vor — wie oft sich jemand meldet, ist ja bereits die
+/// Quantität. Nur ein Richtwert, kein fester Automatismus: die Lehrkraft übernimmt den Vorschlag
+/// per Klick oder ignoriert ihn. Bewusst nur für <see cref="AspectValueType.Scale5"/> (der
+/// Standardtyp des "quantity"-Aspekts) — für individuell umkonfigurierte Aspekttypen gäbe es keine
+/// sinnvolle, unmissverständliche Abbildung.
+/// </summary>
+public static class ParticipationCountSuggestion
+{
+    public static int? SuggestQuantity(AspectValueType type, int raisedHandCount)
+    {
+        if (type != AspectValueType.Scale5) return null;
+        return raisedHandCount switch
+        {
+            0 => -2,
+            1 => -1,
+            2 or 3 => 0,
+            4 or 5 => 1,
+            _ => 2,
+        };
+    }
+}

LehrerApp.Core/Models/Planning.cs

@@ -100,7 +100,10 @@ public class LessonPhaseStep
 }
 
 public enum UnitStatus { Planned, Active, Completed }
-public enum LessonStatus { Planned, Conducted }
+// Planned=0 und Conducted=1 bleiben absichtlich an ihren bisherigen numerischen Positionen:
+// LiteDB hat diese Werte bereits gespeichert. Die neuen Zustände werden nur angehängt, damit
+// vorhandene Daten ohne Migration weiterhin korrekt gelesen werden.
+public enum LessonStatus { Planned = 0, Conducted = 1, Draft = 2, Ready = 3 }
 
 /// <summary>
 /// Katalogeintrag für einen wiederverwendbaren "alternativen Ablauf" (z.B. "Kurzversion" bei

LehrerApp.Core/Models/UntisCache.cs

@@ -0,0 +1,79 @@
+namespace LehrerApp.Core.Models;
+
+/// <summary>
+/// Lokal zwischengespeicherte Zeile aus dem WebUntis-Bericht "Fehlzeiten pro Schüler*in"
+/// (Klassenlehrer-Feature, siehe TODO.md) — 1:1-Abbildung von `UntisClassAbsenceEntryDto`
+/// (LehrerApp.Desktop), damit Fehlzeiten nicht bei jedem Öffnen der Ansicht neu abgerufen werden
+/// müssen. <c>Date</c> bewusst als <c>int</c> (yyyyMMdd) wie die DTOs statt <c>DateOnly</c>/
+/// <c>DateTime</c> — vermeidet die LiteDB-<c>DateTime</c>-Kind-Tücke (siehe CLAUDE.md) und ist
+/// direkt für Bereichs-Queries nutzbar.
+/// </summary>
+public class UntisAbsenceCacheEntry
+{
+    public Guid Id { get; set; } = Guid.NewGuid();
+    public string ClassName { get; set; } = "";
+    public string StudentName { get; set; } = "";
+    public int? ExternKey { get; set; }
+    public int Date { get; set; }
+    public int AbsentPeriods { get; set; }
+    public int AbsentMinutes { get; set; }
+    public string? TeacherUsernames { get; set; }
+    public string? Subject { get; set; }
+    public string? AbsenceReason { get; set; }
+    public string? Note { get; set; }
+    public int? EntryId { get; set; }
+    public string? HandledOn { get; set; }
+    public bool Counts { get; set; }
+    public string? ExcuseNote { get; set; }
+    public int? PeriodNumber { get; set; }
+    public string? Status { get; set; }
+    public bool CountsAsFullDay { get; set; }
+}
+
+/// <summary>Lokal zwischengespeicherte Zeile aus dem "-alle-"-Klassenbuchbericht, gefiltert auf
+/// Einträge anderer Lehrkräfte (Klassenlehrer-Feature) — 1:1-Abbildung von
+/// `UntisForeignClassRegisterEventDto` (LehrerApp.Desktop).</summary>
+public class UntisClassRegisterCacheEntry
+{
+    public Guid Id { get; set; } = Guid.NewGuid();
+    public string ClassName { get; set; } = "";
+    public int Date { get; set; }
+    public string? Subject { get; set; }
+    public string StudentName { get; set; } = "";
+    public string? TeacherUsername { get; set; }
+    public string? CategoryName { get; set; }
+    public string? CategoryGroup { get; set; }
+    public string? Text { get; set; }
+}
+
+/// <summary>Lokal zwischengespeicherte Zeile aus dem WebUntis-Schülerreport, eingeschränkt auf die
+/// für die Klassenlehrer-Übersicht nötigen Felder (Roster-Namen) — anders als Fehlzeiten/
+/// Klassenbuch keine Historie, sondern immer nur der zuletzt abgerufene Stand einer Klasse
+/// (siehe <see cref="UntisClassRegisterCacheEntry"/> für den Grund, warum es trotzdem ein eigenes
+/// Modell statt Wiederverwendung des vollen Schülerreport-DTOs ist: nur diese zwei Felder werden
+/// für den Roster-Abgleich tatsächlich gebraucht).</summary>
+public class UntisStudentRosterCacheEntry
+{
+    public Guid Id { get; set; } = Guid.NewGuid();
+    public string ClassName { get; set; } = "";
+    public int? ExternKey { get; set; }
+    public string DisplayName { get; set; } = "";
+}
+
+public enum UntisCacheKind { Absences, ClassRegister, Roster }
+
+/// <summary>
+/// Ein Datensatz pro (<see cref="ClassName"/>, <see cref="Kind"/>): wann das "heiße" Fenster
+/// (die letzten Tage, deren Status sich noch ändern kann) zuletzt aufgefrischt wurde, und wie weit
+/// die "kalte", als endgültig angenommene Historie bereits lückenlos zurückreicht. Getrennt von den
+/// Cache-Zeilen selbst, weil ein Fenster ohne Treffer (z.B. eine ereignislose Woche) sonst keine
+/// Zeile hinterließe, aus der sich "zuletzt abgerufen am…" ableiten ließe.
+/// </summary>
+public class UntisCacheFetchState
+{
+    public Guid Id { get; set; } = Guid.NewGuid();
+    public string ClassName { get; set; } = "";
+    public UntisCacheKind Kind { get; set; }
+    public DateTime? HotWindowFetchedAt { get; set; }
+    public int? ColdCoverageStartDate { get; set; }
+}

LehrerApp.Core/Models/Weather.cs

@@ -42,6 +42,10 @@ public sealed class WeatherForecastHour
     public double? WindSpeedKmh { get; set; }
     public double? WindGustKmh { get; set; }
     public double? PrecipitationMm { get; set; }
+    /// <summary>Stündliche MOSMIX-Wahrscheinlichkeit für mehr als 0,1 mm Niederschlag.</summary>
+    public double? PrecipitationProbabilityPercent { get; set; }
+    /// <summary>MOSMIX-Sonnenscheindauer der letzten Stunde, in Minuten.</summary>
+    public double? SunshineDurationMinutes { get; set; }
     public double? CloudCoverPercent { get; set; }
     public int? WeatherCode { get; set; }
 }

LehrerApp.Core/Models/Workload.cs

@@ -24,6 +24,10 @@ public class Documentation : IHasAttachments
     /// <summary>Im Unterricht schnell erfasst und noch inhaltlich nachzuarbeiten.</summary>
     public bool IsDraft { get; set; }
     public bool IsConfidential { get; set; }
+    /// <summary>Für die pädagogische Arbeit/Leistungsbewertung gedacht, aber nicht für den
+    /// WebUntis-Klassenbuch-Abgleich vorgesehen - blendet den Eintrag im Abgleichsdialog
+    /// (WebUntisDocumentationComparisonViewModel) aus dem Zwischenablage-Vorschlag aus.</summary>
+    public bool ExcludeFromWebUntisSync { get; set; }
     public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
     public DateTime UpdatedAt { get; set; } = DateTime.UtcNow;
     // Löschen entfernt den Eintrag nicht hart, sondern markiert ihn nur (Nachvollziehbarkeit, 5.1.4).
@@ -89,7 +93,7 @@ public interface IHasAttachments
     List<DocumentAttachment> Attachments { get; }
 }
 // Hinten angefügt, damit die numerischen Werte bereits gespeicherter LiteDB-Einträge stabil bleiben.
-public enum DocumentationType { Conversation, Incident, SupportPlan, Absence, ParentCall, ParentLetter }
+public enum DocumentationType { Conversation, Incident, SupportPlan, Absence, ParentCall, ParentLetter, Planning }
 public enum SupportStatus { Active, Completed, Paused }
 
 public class WorkTask

LehrerApp.Core/Services/BackupService.cs

@@ -14,6 +14,13 @@ public class BackupService
 
     public string BackupDirectory => _backupDirectory;
 
+    /// Optionales zweites Sicherungsziel (z.B. USB-Stick, Netzlaufwerk) — Backups liegen sonst
+    /// ausschließlich neben der Live-Datenbank und sind bei einem Plattenausfall oder einem
+    /// versehentlich gelöschten Profilverzeichnis wertlos. Wird von außen gesetzt (Desktop-Settings,
+    /// siehe BackupSettingsService); bewusst best-effort — ist das Ziel beim Sichern nicht
+    /// erreichbar (Stick nicht eingesteckt, Freigabe offline), bleibt nur das Hauptbackup bestehen.
+    public string? SecondaryBackupDirectory { get; set; }
+
     public BackupService(string appDataPath)
     {
         _backupDirectory = Path.Combine(appDataPath, "backups");
@@ -34,9 +41,36 @@ public class BackupService
         File.Copy(databasePath, target, overwrite: true);
 
         PruneOldBackups(keepCount);
+
+        if (!string.IsNullOrWhiteSpace(SecondaryBackupDirectory))
+            TryMirrorToSecondary(target, fileName, keepCount);
+
         return target;
     }
 
+    private void TryMirrorToSecondary(string sourcePath, string fileName, int keepCount)
+    {
+        try
+        {
+            Directory.CreateDirectory(SecondaryBackupDirectory!);
+            File.Copy(sourcePath, Path.Combine(SecondaryBackupDirectory!, fileName), overwrite: true);
+
+            foreach (var stale in Directory.GetFiles(SecondaryBackupDirectory!, "lehrerapp-*.db")
+                         .Select(p => new FileInfo(p))
+                         .OrderByDescending(f => f.LastWriteTime)
+                         .Skip(keepCount))
+            {
+                try { stale.Delete(); }
+                catch { /* nächster Lauf versucht es erneut */ }
+            }
+        }
+        catch
+        {
+            // Sicherungsziel nicht erreichbar — das Hauptbackup (_backupDirectory) ist davon
+            // unberührt, ein manuelles/automatisches Backup soll daran nicht scheitern.
+        }
+    }
+
     public List<BackupInfo> ListBackups() =>
         Directory.GetFiles(_backupDirectory, "lehrerapp-*.db")
             .Select(p => new BackupInfo(p, File.GetLastWriteTime(p), new FileInfo(p).Length))

LehrerApp.Core/Services/DashboardSettingsService.cs

@@ -15,7 +15,8 @@ public sealed class DashboardSettingsService
     public static readonly string[] DefaultCardOrder =
     [
         "today", "tasks", "calendar", "excuses", "upcoming",
-        "corrections", "unplanned", "alerts", "attendance", "support", "groups",
+        "corrections", "unplanned", "alerts", "attendance", "support", "groups", "examload",
+        "missingteachingtime",
     ];
 
     private readonly string _configPath;

LehrerApp.Core/Services/ExamPriorityService.cs

@@ -0,0 +1,67 @@
+using LehrerApp.Core.Models;
+
+namespace LehrerApp.Core.Services;
+
+/// Zählt den Korrekturfortschritt einer Klausur aus den vorhandenen Ergebnissen, statt einen
+/// eigenen "Korrektur läuft"-Status pflegen zu müssen — ein `ExamResult` gilt als erledigt, sobald
+/// entweder Punkte/Note eingetragen oder der Schüler als abwesend markiert wurde. Von
+/// DashboardViewModel (Karte "Offene Korrekturen") und ExamsOverviewViewModel (Klausuren-
+/// Hauptseite) gemeinsam genutzt, damit beide Stellen exakt dieselbe Zahl zeigen.
+public static class ExamCorrectionCounter
+{
+    public static (int Expected, int Evaluated) Count(Exam exam, List<GroupMembership> groupMemberships,
+        List<ExamResult> examResults)
+    {
+        var expected = groupMemberships.Count(m => GroupMembershipService.IsActiveOn(m, exam.Date));
+        var evaluated = examResults.Count(r => r.Absent || !string.IsNullOrWhiteSpace(r.Grade) || r.Points.Count > 0);
+        return (expected, Math.Min(evaluated, expected));
+    }
+}
+
+public enum ExamListStatus { Planned, AwaitingCorrection, CorrectionInProgress, CorrectionStuck, AwaitingReturn, Returned }
+
+public readonly record struct ExamPriorityInfo(ExamListStatus Status, double Score);
+
+/// Ordnet Klausuren für die Klausuren-Hauptseite nach einem unsichtbaren Prioritäts-Score statt
+/// nach Datum: unbearbeitete/überfällige Korrekturen oben, erledigte unten. "Korrektur läuft"
+/// wird bewusst nicht als eigener, manuell zu pflegender Status abgelegt (siehe
+/// `ExamCorrectionCounter`) — bleibt eine Klausur trotzdem lange in Bearbeitung hängen (typischer
+/// Grund: ein einzelner nie nachschreibender Schüler), fällt sie nach `StuckAfterDays` aus der
+/// dringenden Zone in eine ruhige "hängt fest"-Einstufung, statt dauerhaft oben zu kleben.
+public static class ExamPriorityService
+{
+    public const int StuckAfterDays = 21;
+    private const int CorrectionGraceDays = 3;
+
+    public static ExamPriorityInfo Evaluate(Exam exam, int expected, int evaluated, DateOnly today)
+    {
+        if (exam.Status == ExamStatus.Returned)
+            return new ExamPriorityInfo(ExamListStatus.Returned, -100);
+
+        if (exam.Status == ExamStatus.Graded)
+            return new ExamPriorityInfo(ExamListStatus.AwaitingReturn, 300);
+
+        if (exam.Status == ExamStatus.Planned)
+        {
+            var daysUntil = exam.Date.DayNumber - today.DayNumber;
+            return new ExamPriorityInfo(ExamListStatus.Planned, Math.Clamp(150 - daysUntil, 20, 150));
+        }
+
+        // Status == Conducted: Korrekturfortschritt entscheidet über die genaue Einstufung.
+        var daysSince = today.DayNumber - exam.Date.DayNumber;
+
+        if (evaluated <= 0)
+        {
+            var score = daysSince <= CorrectionGraceDays ? 400 + daysSince * 10 : 600 + daysSince;
+            return new ExamPriorityInfo(ExamListStatus.AwaitingCorrection, score);
+        }
+
+        if (expected > 0 && evaluated >= expected)
+            return new ExamPriorityInfo(ExamListStatus.AwaitingReturn, 300);
+
+        if (daysSince > StuckAfterDays)
+            return new ExamPriorityInfo(ExamListStatus.CorrectionStuck, 90);
+
+        return new ExamPriorityInfo(ExamListStatus.CorrectionInProgress, 400 + daysSince * 3);
+    }
+}

LehrerApp.Core/Services/ExamWeekLoadService.cs

@@ -0,0 +1,54 @@
+using System.Globalization;
+using LehrerApp.Core.Models;
+
+namespace LehrerApp.Core.Services;
+
+/// <summary>
+/// Zählt eigene Klausuren pro ISO-Kalenderwoche über alle Lerngruppen hinweg. Nutzer-Feedback:
+/// die klassenbezogene Kollisionsprüfung (mehrere Klausuren einer einzelnen Klasse in einer
+/// Woche) übernimmt bereits der schulische Klausurplaner (externes Klassenbuch) — was dort
+/// fehlt, ist die persönliche Belastung der Lehrkraft: mehr eigene Klausuren in derselben Woche
+/// bedeuten unabhängig von der Klasse mehr Erstellungsaufwand vorher und mehr Korrekturaufwand
+/// danach. Da eine LiteDB-Datei genau einem Nutzer gehört (siehe CLAUDE.md), sind "alle
+/// Klausuren in der Datenbank" bereits gleichbedeutend mit "meine Klausuren".
+/// </summary>
+public static class ExamWeekLoadService
+{
+    /// Ab dieser Anzahl eigener Klausuren in derselben Woche gilt die Woche als spürbar belastet.
+    /// Nutzer-Feedback: zwei Klausuren aus zwei unterrichteten Fächern in derselben Woche sind
+    /// normal, eine dritte ist die eigentliche Häufung.
+    public const int WarningThreshold = 3;
+
+    /// Anzahl Klausuren (ohne <paramref name="excludeExamId"/>, z.B. die gerade im Dialog
+    /// bearbeitete), die in dieselbe ISO-Kalenderwoche wie <paramref name="date"/> fallen.
+    public static int CountInSameWeek(IEnumerable<Exam> allExams, DateOnly date, Guid? excludeExamId = null)
+    {
+        var (year, week) = IsoWeek(date);
+        return allExams.Count(e => e.Id != excludeExamId && IsoWeek(e.Date) == (year, week));
+    }
+
+    /// Gruppiert die übergebenen Klausuren nach ISO-Kalenderwoche und liefert nur die Wochen mit
+    /// mindestens <see cref="WarningThreshold"/> Klausuren, chronologisch sortiert — für einen
+    /// vorausschauenden Überblick (z.B. Dashboard), nicht für die Einzelprüfung beim Anlegen.
+    public static List<ExamWeekLoad> FindOverloadedWeeks(IEnumerable<Exam> exams) =>
+        exams
+            .GroupBy(e => IsoWeek(e.Date))
+            .Where(g => g.Count() >= WarningThreshold)
+            .Select(g => new ExamWeekLoad(g.Key.Year, g.Key.Week, WeekStart(g.Key.Year, g.Key.Week), g.Count()))
+            .OrderBy(w => w.WeekStart)
+            .ToList();
+
+    private static (int Year, int Week) IsoWeek(DateOnly date)
+    {
+        var dt = date.ToDateTime(TimeOnly.MinValue);
+        return (ISOWeek.GetYear(dt), ISOWeek.GetWeekOfYear(dt));
+    }
+
+    private static DateOnly WeekStart(int isoYear, int isoWeek) =>
+        DateOnly.FromDateTime(ISOWeek.ToDateTime(isoYear, isoWeek, DayOfWeek.Monday));
+}
+
+public readonly record struct ExamWeekLoad(int IsoYear, int IsoWeek, DateOnly WeekStart, int ExamCount)
+{
+    public DateOnly WeekEnd => WeekStart.AddDays(6);
+}

LehrerApp.Core/Services/GradingService.cs

@@ -77,13 +77,29 @@ public class GradingService
     public double WeightedAverage(List<(string Grade, double Weight)> grades)
     {
         var numeric = grades
-            .Select(g => (Value: int.TryParse(g.Grade, out var n) ? (int?)n : null, g.Weight))
+            .Select(g => (Value: ParseGradeValue(g.Grade), g.Weight))
             .Where(g => g.Value.HasValue).ToList();
         if (numeric.Count == 0) return 0;
         var total = numeric.Sum(g => g.Weight);
         return total == 0 ? 0 : numeric.Sum(g => g.Value!.Value * g.Weight) / total;
     }
 
+    /// Wandelt eine Notenangabe mit optionaler Tendenz ("3+", "2-") in einen rechnerischen
+    /// Notenwert um. Tendenzen verschieben um ein Drittel in Richtung der besseren Note
+    /// (z.B. "3+" → 2,67, "2-" → 2,33) — der in deutschen Notensystemen übliche Drittelabstand.
+    private static double? ParseGradeValue(string grade)
+    {
+        var trimmed = grade.Trim();
+        if (trimmed.Length == 0) return null;
+
+        var tendency = 0.0;
+        var core = trimmed;
+        if (core.EndsWith('+')) { tendency = -1.0 / 3.0; core = core[..^1].TrimEnd(); }
+        else if (core.EndsWith('-')) { tendency = 1.0 / 3.0; core = core[..^1].TrimEnd(); }
+
+        return int.TryParse(core, out var n) ? n + tendency : null;
+    }
+
     /// Rundet einen rechnerischen Notenwert auf eine ganze Note/Punktzahl.
     /// "Kaufmännisch" rundet bei genau 0,5 immer vom Nullpunkt weg (Standard).
     /// "Pädagogisch" rundet bei genau 0,5 in Richtung der besseren Note

LehrerApp.Core/Services/GroupRolloverService.cs

@@ -60,6 +60,9 @@ public sealed class GroupRolloverService(
             IsActive = true,
             IsOwnClass = source.IsOwnClass,
             IsDifferentiated = source.IsDifferentiated,
+            PreviousGroupId = source.Id,
+            // WebUntisLessonId bewusst nicht übernommen: WebUntis vergibt sie pro Schuljahr neu,
+            // eine übernommene alte lsid würde in der Folgegruppe stumm falsche Fehlzeiten liefern.
         };
 
         var sourceWasActive = source.IsActive;

LehrerApp.Core/Services/LessonSchedulingService.cs

@@ -0,0 +1,99 @@
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+
+namespace LehrerApp.Core.Services;
+
+/// <summary>Gemeinsame Terminlogik für Verschieben und Trennen von Stunden.</summary>
+public sealed class LessonSchedulingService(ILessonRepository lessons)
+{
+    public void Move(Lesson lesson, DateOnly newDate, int? newPeriod, bool shiftFollowing)
+    {
+        EnsureTargetIsFree(lesson, newDate, newPeriod);
+        var oldDate = lesson.Date;
+        var delta = newDate.DayNumber - oldDate.DayNumber;
+
+        if (shiftFollowing && delta != 0)
+        {
+            foreach (var other in lessons.GetByUnit(lesson.UnitId))
+            {
+                if (other.Id == lesson.Id || other.Status == LessonStatus.Conducted || other.Date <= oldDate)
+                    continue;
+                other.Date = other.Date.AddDays(delta);
+                lessons.Save(other);
+            }
+        }
+
+        lesson.Date = newDate;
+        if (newPeriod.HasValue) lesson.LessonNumber = newPeriod;
+        lessons.Save(lesson);
+    }
+
+    public Lesson SplitAndMoveSecondPart(Lesson source, int splitAfterMinutes, DateOnly newDate,
+        int newPeriod, TimeOnly? newStartTime)
+    {
+        if (splitAfterMinutes <= 0 || source.Phases.Sum(p => p.DurationMinutes) <= splitAfterMinutes)
+            throw new InvalidOperationException("Der Verlauf reicht nicht über die erste Stunde hinaus.");
+        EnsureTargetIsFree(source, newDate, newPeriod);
+
+        var first = new List<LessonPhaseStep>();
+        var second = new List<LessonPhaseStep>();
+        var elapsed = 0;
+        foreach (var phase in source.Phases)
+        {
+            var remainingInFirst = splitAfterMinutes - elapsed;
+            if (remainingInFirst <= 0)
+                second.Add(Clone(phase, phase.DurationMinutes));
+            else if (phase.DurationMinutes <= remainingInFirst)
+                first.Add(Clone(phase, phase.DurationMinutes));
+            else
+            {
+                first.Add(Clone(phase, remainingInFirst));
+                second.Add(Clone(phase, phase.DurationMinutes - remainingInFirst));
+            }
+            elapsed += phase.DurationMinutes;
+        }
+
+        source.Phases = first;
+        var continuation = new Lesson
+        {
+            UnitId = source.UnitId,
+            GroupId = source.GroupId,
+            Date = newDate,
+            LessonNumber = newPeriod,
+            StartTime = newStartTime,
+            Topic = string.IsNullOrWhiteSpace(source.Topic) ? "Fortsetzung" : $"{source.Topic} – Fortsetzung",
+            Phases = second,
+            Homework = source.Homework,
+            HomeworkChecked = source.HomeworkChecked,
+            HomeworkCheckDismissed = source.HomeworkCheckDismissed,
+            Reflection = source.Reflection,
+            Status = source.Status == LessonStatus.Conducted ? LessonStatus.Draft : source.Status,
+        };
+        source.Homework = null;
+        source.HomeworkChecked = false;
+        source.HomeworkCheckDismissed = false;
+        source.Reflection = null;
+        lessons.Save(source);
+        lessons.Save(continuation);
+        return continuation;
+    }
+
+    private void EnsureTargetIsFree(Lesson source, DateOnly date, int? period)
+    {
+        if (period is null) return;
+        var occupied = lessons.GetByGroupAndDate(source.GroupId, date)
+            .Any(l => l.Id != source.Id && l.LessonNumber == period);
+        if (occupied)
+            throw new InvalidOperationException($"Für die Lerngruppe existiert am {date:dd.MM.yyyy} in der {period}. Stunde bereits eine Planung.");
+    }
+
+    private static LessonPhaseStep Clone(LessonPhaseStep source, int duration) => new()
+    {
+        Name = source.Name,
+        DurationMinutes = duration,
+        Activity = source.Activity,
+        Material = source.Material,
+        Shorthand = source.Shorthand,
+        AlternativePathId = source.AlternativePathId,
+    };
+}

LehrerApp.Core/Services/LetterTemplateService.cs

@@ -1,316 +0,0 @@
-using System.IO.Compression;
-using System.Text.Json;
-using System.Xml.Linq;
-
-namespace LehrerApp.Core.Services;
-
-public enum TemplateIssueSeverity
-{
-    Warning,
-    StrongWarning,
-    Error,
-}
-
-public sealed record LetterPlaceholder(string Tag, string Description);
-
-public sealed record TemplateValidationIssue(
-    TemplateIssueSeverity Severity,
-    string Message,
-    string? Tag = null,
-    string? SuggestedTag = null);
-
-public sealed record TemplateValidationResult(
-    IReadOnlyList<string> Tags,
-    IReadOnlyList<TemplateValidationIssue> Issues)
-{
-    public bool CanGenerate => Issues.All(i => i.Severity != TemplateIssueSeverity.Error);
-    public bool HasStrongWarnings => Issues.Any(i => i.Severity == TemplateIssueSeverity.StrongWarning);
-}
-
-public sealed class LetterTemplateInfo
-{
-    public Guid Id { get; set; } = Guid.NewGuid();
-    public string Name { get; set; } = "";
-    public string StoredFileName { get; set; } = "";
-    public string OriginalFileName { get; set; } = "";
-    public DateTime ImportedAt { get; set; } = DateTime.UtcNow;
-}
-
-/// <summary>
-/// Verwaltet DOCX-Briefvorlagen und befüllt Word-Inhaltssteuerelemente anhand ihres Tags.
-/// Die Originalvorlage wird nie verändert.
-/// </summary>
-public sealed class LetterTemplateService
-{
-    private static readonly XNamespace W = "http://schemas.openxmlformats.org/wordprocessingml/2006/main";
-    private static readonly JsonSerializerOptions JsonOptions = new() { WriteIndented = true };
-
-    public static IReadOnlyList<LetterPlaceholder> SupportedPlaceholders { get; } =
-    [
-        new("Student.FirstName", "Vorname des Schülers"),
-        new("Student.LastName", "Nachname des Schülers"),
-        new("Contact.Name", "Name des ausgewählten Kontakts"),
-        new("Contact.Address", "Vollständige Anschrift (mehrzeilig)"),
-        new("Contact.Street", "Straße und Hausnummer"),
-        new("Contact.PostalCode", "Postleitzahl"),
-        new("Contact.City", "Ort"),
-        new("Letter.Salutation", "Gespeicherte Briefanrede des Kontakts"),
-        new("Group.Name", "Ausgewählte Lerngruppe"),
-        new("SchoolYear", "Schuljahr der ausgewählten Gruppe"),
-        new("CurrentDate", "Gewähltes Briefdatum"),
-    ];
-
-    private readonly string _templateDirectory;
-    private readonly string _indexPath;
-
-    public LetterTemplateService(string appDataPath)
-    {
-        _templateDirectory = Path.Combine(appDataPath, "letter-templates");
-        _indexPath = Path.Combine(_templateDirectory, "templates.json");
-        Directory.CreateDirectory(_templateDirectory);
-    }
-
-    public IReadOnlyList<LetterTemplateInfo> GetTemplates() => LoadIndex()
-        .OrderBy(t => t.Name, StringComparer.CurrentCultureIgnoreCase)
-        .ToList();
-
-    public string GetTemplatePath(LetterTemplateInfo template) =>
-        Path.Combine(_templateDirectory, template.StoredFileName);
-
-    public LetterTemplateInfo Import(string sourcePath, string? displayName = null)
-    {
-        var validation = Validate(sourcePath);
-        if (!validation.CanGenerate)
-            throw new InvalidDataException(validation.Issues.First(i => i.Severity == TemplateIssueSeverity.Error).Message);
-
-        var templates = LoadIndex();
-        var info = new LetterTemplateInfo
-        {
-            Name = string.IsNullOrWhiteSpace(displayName)
-                ? Path.GetFileNameWithoutExtension(sourcePath)
-                : displayName.Trim(),
-            OriginalFileName = Path.GetFileName(sourcePath),
-        };
-        info.StoredFileName = $"{info.Id:N}.docx";
-        File.Copy(sourcePath, GetTemplatePath(info), overwrite: false);
-        templates.Add(info);
-        SaveIndex(templates);
-        return info;
-    }
-
-    public void Delete(Guid id)
-    {
-        var templates = LoadIndex();
-        var template = templates.FirstOrDefault(t => t.Id == id);
-        if (template is null) return;
-        var path = GetTemplatePath(template);
-        if (File.Exists(path)) File.Delete(path);
-        templates.Remove(template);
-        SaveIndex(templates);
-    }
-
-    public TemplateValidationResult Validate(LetterTemplateInfo template) =>
-        Validate(GetTemplatePath(template));
-
-    public TemplateValidationResult Validate(string path)
-    {
-        var tags = new List<string>();
-        var issues = new List<TemplateValidationIssue>();
-
-        if (!File.Exists(path))
-            return Error("Die Vorlagendatei wurde nicht gefunden.");
-        if (!string.Equals(Path.GetExtension(path), ".docx", StringComparison.OrdinalIgnoreCase))
-            return Error("Die Vorlage muss eine DOCX-Datei sein.");
-
-        try
-        {
-            using var archive = ZipFile.OpenRead(path);
-            var xmlEntries = WordXmlEntries(archive).ToList();
-            if (xmlEntries.All(e => !string.Equals(e.FullName, "word/document.xml", StringComparison.OrdinalIgnoreCase)))
-                return Error("Die Datei ist kein gültiges Word-DOCX-Dokument.");
-
-            foreach (var entry in xmlEntries)
-            {
-                using var stream = entry.Open();
-                var document = XDocument.Load(stream, LoadOptions.PreserveWhitespace);
-                foreach (var control in document.Descendants(W + "sdt"))
-                {
-                    var tag = control.Element(W + "sdtPr")?.Element(W + "tag")?.Attribute(W + "val")?.Value?.Trim();
-                    if (string.IsNullOrWhiteSpace(tag))
-                    {
-                        issues.Add(new(TemplateIssueSeverity.StrongWarning,
-                            $"Ein Inhaltssteuerelement in {PartLabel(entry.FullName)} besitzt keinen Tag und kann nicht befüllt werden."));
-                        continue;
-                    }
-                    tags.Add(tag);
-                }
-            }
-        }
-        catch (InvalidDataException)
-        {
-            return Error("Die Datei ist beschädigt oder kein gültiges DOCX-Dokument.");
-        }
-        catch (System.Xml.XmlException)
-        {
-            return Error("Die Word-Vorlage enthält ungültiges XML und kann nicht gelesen werden.");
-        }
-        catch (IOException ex)
-        {
-            return Error($"Die Vorlage konnte nicht geöffnet werden: {ex.Message}");
-        }
-
-        if (tags.Count == 0 && issues.Count == 0)
-            issues.Add(new(TemplateIssueSeverity.Warning,
-                "Die Vorlage enthält keine Inhaltssteuerelemente. Es werden keine Felder befüllt."));
-
-        foreach (var tag in tags.Distinct(StringComparer.Ordinal))
-        {
-            if (SupportedPlaceholders.Any(p => p.Tag == tag)) continue;
-            var suggestion = FindSuggestion(tag);
-            issues.Add(suggestion is null
-                ? new(TemplateIssueSeverity.Warning,
-                    $"Der unbekannte Tag „{tag}“ wird nicht befüllt.", tag)
-                : new(TemplateIssueSeverity.StrongWarning,
-                    $"Wahrscheinlicher Schreibfehler: „{tag}“. Meinten Sie „{suggestion}“?", tag, suggestion));
-        }
-
-        return new(tags.Distinct(StringComparer.Ordinal).OrderBy(t => t).ToList(), issues);
-
-        TemplateValidationResult Error(string message) =>
-            new([], [new(TemplateIssueSeverity.Error, message)]);
-    }
-
-    public void Generate(string templatePath, string outputPath,
-        IReadOnlyDictionary<string, string?> values)
-    {
-        var validation = Validate(templatePath);
-        if (!validation.CanGenerate)
-            throw new InvalidDataException(validation.Issues.First(i => i.Severity == TemplateIssueSeverity.Error).Message);
-
-        var outputDirectory = Path.GetDirectoryName(outputPath);
-        if (!string.IsNullOrEmpty(outputDirectory)) Directory.CreateDirectory(outputDirectory);
-
-        using var source = ZipFile.OpenRead(templatePath);
-        using var target = ZipFile.Open(outputPath, ZipArchiveMode.Create);
-        foreach (var entry in source.Entries)
-        {
-            var targetEntry = target.CreateEntry(entry.FullName, CompressionLevel.Optimal);
-            targetEntry.LastWriteTime = entry.LastWriteTime;
-            using var input = entry.Open();
-            using var output = targetEntry.Open();
-
-            if (!IsWordXmlEntry(entry))
-            {
-                input.CopyTo(output);
-                continue;
-            }
-
-            var document = XDocument.Load(input, LoadOptions.PreserveWhitespace);
-            foreach (var control in document.Descendants(W + "sdt").ToList())
-            {
-                var tag = control.Element(W + "sdtPr")?.Element(W + "tag")?.Attribute(W + "val")?.Value?.Trim();
-                if (tag is null || !values.TryGetValue(tag, out var value)) continue;
-                ReplaceContent(control.Element(W + "sdtContent"), value ?? "");
-            }
-            document.Save(output, SaveOptions.DisableFormatting);
-        }
-    }
-
-    private static void ReplaceContent(XElement? content, string value)
-    {
-        if (content is null) return;
-        var paragraph = content.Elements(W + "p").FirstOrDefault();
-        XElement run;
-
-        if (paragraph is not null)
-        {
-            run = paragraph.Descendants(W + "r").FirstOrDefault() ?? new XElement(W + "r");
-            var paragraphProperties = paragraph.Element(W + "pPr");
-            var runProperties = run.Element(W + "rPr") is { } rp ? new XElement(rp) : null;
-            paragraph.RemoveNodes();
-            if (paragraphProperties is not null) paragraph.Add(paragraphProperties);
-            run = new XElement(W + "r");
-            if (runProperties is not null) run.Add(runProperties);
-            paragraph.Add(run);
-            foreach (var extra in content.Elements(W + "p").Skip(1).ToList()) extra.Remove();
-            foreach (var node in content.Nodes().Where(n => n is XElement e && e.Name != W + "p").ToList()) node.Remove();
-        }
-        else
-        {
-            var firstRun = content.Descendants(W + "r").FirstOrDefault();
-            var runProperties = firstRun?.Element(W + "rPr") is { } rp ? new XElement(rp) : null;
-            content.RemoveNodes();
-            run = new XElement(W + "r");
-            if (runProperties is not null) run.Add(runProperties);
-            content.Add(run);
-        }
-
-        var lines = value.Replace("\r\n", "\n", StringComparison.Ordinal).Replace('\r', '\n').Split('\n');
-        for (var i = 0; i < lines.Length; i++)
-        {
-            if (i > 0) run.Add(new XElement(W + "br"));
-            run.Add(new XElement(W + "t", new XAttribute(XNamespace.Xml + "space", "preserve"), lines[i]));
-        }
-    }
-
-    private static IEnumerable<ZipArchiveEntry> WordXmlEntries(ZipArchive archive) =>
-        archive.Entries.Where(IsWordXmlEntry);
-
-    private static bool IsWordXmlEntry(ZipArchiveEntry entry) =>
-        entry.FullName.StartsWith("word/", StringComparison.OrdinalIgnoreCase)
-        && entry.FullName.EndsWith(".xml", StringComparison.OrdinalIgnoreCase);
-
-    private static string PartLabel(string path) => path switch
-    {
-        "word/document.xml" => "Dokumenttext",
-        var p when p.StartsWith("word/header", StringComparison.OrdinalIgnoreCase) => "einer Kopfzeile",
-        var p when p.StartsWith("word/footer", StringComparison.OrdinalIgnoreCase) => "einer Fußzeile",
-        _ => $"dem Dokumentteil „{Path.GetFileName(path)}“",
-    };
-
-    private static string? FindSuggestion(string unknown)
-    {
-        var candidate = SupportedPlaceholders
-            .Select(p => (p.Tag, Distance: Levenshtein(unknown.ToLowerInvariant(), p.Tag.ToLowerInvariant())))
-            .OrderBy(x => x.Distance)
-            .ThenBy(x => x.Tag)
-            .First();
-        var threshold = candidate.Tag.Length >= 12 ? 3 : 2;
-        return candidate.Distance <= threshold ? candidate.Tag : null;
-    }
-
-    private static int Levenshtein(string left, string right)
-    {
-        var previous = Enumerable.Range(0, right.Length + 1).ToArray();
-        for (var i = 1; i <= left.Length; i++)
-        {
-            var current = new int[right.Length + 1];
-            current[0] = i;
-            for (var j = 1; j <= right.Length; j++)
-                current[j] = Math.Min(Math.Min(current[j - 1] + 1, previous[j] + 1),
-                    previous[j - 1] + (left[i - 1] == right[j - 1] ? 0 : 1));
-            previous = current;
-        }
-        return previous[right.Length];
-    }
-
-    private List<LetterTemplateInfo> LoadIndex()
-    {
-        if (!File.Exists(_indexPath)) return [];
-        try
-        {
-            return JsonSerializer.Deserialize<List<LetterTemplateInfo>>(File.ReadAllText(_indexPath), JsonOptions) ?? [];
-        }
-        catch (JsonException)
-        {
-            return [];
-        }
-    }
-
-    private void SaveIndex(List<LetterTemplateInfo> templates)
-    {
-        var temporaryPath = _indexPath + ".tmp";
-        File.WriteAllText(temporaryPath, JsonSerializer.Serialize(templates, JsonOptions));
-        File.Move(temporaryPath, _indexPath, overwrite: true);
-    }
-}

LehrerApp.Core/Services/ReportGradeTargetCalculator.cs

@@ -0,0 +1,48 @@
+using LehrerApp.Core.Models;
+
+namespace LehrerApp.Core.Services;
+
+/// Welcher der drei Leistungsbereiche (siehe GradingScheme) bei der Zielnoten-Frage der
+/// gesuchte/unbekannte ist.
+public enum GradeBucketKind { Exams, Participation, Other }
+
+public readonly record struct TargetGradeResult(double RequiredAverage, bool IsAchievable);
+
+/// <summary>
+/// Beantwortet die Zielnoten-Frage "Was brauche ich noch, um Zeugnisnote X zu erreichen?"
+/// (Nutzer-Feedback) — kehrt <see cref="GradingService.CalculateReportGrade"/> um: löst nach
+/// dem Durchschnitt eines gewählten Bereichs auf, der zusammen mit den bekannten Durchschnitten
+/// der übrigen Bereiche (gewichtet nach <see cref="GradingScheme"/>) genau die Zielnote ergibt.
+/// Bereiche ohne bekannten Durchschnitt (z.B. noch keine Mitarbeitsnote im Halbjahr) fließen
+/// nicht in die bekannte Seite der Gleichung ein — exakt dieselbe Normierung wie
+/// <see cref="GradingService.CalculateReportGrade"/> bei fehlenden Bereichen.
+/// </summary>
+public static class ReportGradeTargetCalculator
+{
+    public static TargetGradeResult? SolveRequiredAverage(double target, GradeBucketKind solveFor,
+        double? examsAverage, double? participationAverage, double? otherAverage,
+        GradingScheme scheme, GradingSystem system)
+    {
+        var solvePercent = solveFor switch
+        {
+            GradeBucketKind.Exams => scheme.ExamsPercent,
+            GradeBucketKind.Participation => scheme.ParticipationPercent,
+            _ => scheme.OtherPercent,
+        };
+        // Dieser Bereich fließt laut Gewichtungsschema gar nicht in die Zeugnisnote ein —
+        // keine Zielnoten-Frage für ihn beantwortbar.
+        if (solvePercent <= 0) return null;
+
+        var known = new List<(double Avg, double Percent)>();
+        if (solveFor != GradeBucketKind.Exams && examsAverage is { } e) known.Add((e, scheme.ExamsPercent));
+        if (solveFor != GradeBucketKind.Participation && participationAverage is { } p) known.Add((p, scheme.ParticipationPercent));
+        if (solveFor != GradeBucketKind.Other && otherAverage is { } o) known.Add((o, scheme.OtherPercent));
+
+        var totalPercent = known.Sum(k => k.Percent) + solvePercent;
+        var knownContribution = known.Sum(k => k.Avg * k.Percent);
+        var required = (target * totalPercent - knownContribution) / solvePercent;
+
+        var (min, max) = system == GradingSystem.Grades1To6 ? (1.0, 6.0) : (0.0, 15.0);
+        return new TargetGradeResult(required, required >= min && required <= max);
+    }
+}

LehrerApp.Data.Tests/DatabaseEncryptionServiceTests.cs

@@ -60,6 +60,65 @@ public sealed class DatabaseEncryptionServiceTests
         Assert.Single(reopened.GetCollection<BsonDocument>("t").FindAll());
     }
 
+    [Fact]
+    public void CanOpenAndRead_OhneVorhandeneDatei_GibtFalseZurueck()
+    {
+        using var temp = new TempDatabase();
+        var service = new DatabaseEncryptionService();
+
+        Assert.False(service.CanOpenAndRead(temp.Path, null));
+    }
+
+    [Fact]
+    public void CanOpenAndRead_GueltigeUnverschluesselteDatenbank_GibtTrueZurueck()
+    {
+        using var temp = new TempDatabase();
+        using (var db = new LiteDatabase(temp.Path))
+            db.GetCollection<BsonDocument>("t").Insert(new BsonDocument { ["x"] = 1 });
+
+        var service = new DatabaseEncryptionService();
+
+        Assert.True(service.CanOpenAndRead(temp.Path, null));
+    }
+
+    [Fact]
+    public void CanOpenAndRead_GueltigeVerschluesselteDatenbankMitRichtigemPasswort_GibtTrueZurueck()
+    {
+        using var temp = new TempDatabase();
+        using (var db = new LiteDatabase(new ConnectionString(temp.Path) { Password = "geheim123" }))
+            db.GetCollection<BsonDocument>("t").Insert(new BsonDocument { ["x"] = 1 });
+
+        var service = new DatabaseEncryptionService();
+
+        Assert.True(service.CanOpenAndRead(temp.Path, "geheim123"));
+    }
+
+    [Fact]
+    public void CanOpenAndRead_FalschesPasswort_GibtFalseZurueck()
+    {
+        using var temp = new TempDatabase();
+        using (var db = new LiteDatabase(new ConnectionString(temp.Path) { Password = "geheim123" }))
+            db.GetCollection<BsonDocument>("t").Insert(new BsonDocument { ["x"] = 1 });
+
+        var service = new DatabaseEncryptionService();
+
+        Assert.False(service.CanOpenAndRead(temp.Path, "falsch"));
+    }
+
+    [Fact]
+    public void CanOpenAndRead_BeschaedigteDatei_GibtFalseZurueck()
+    {
+        using var temp = new TempDatabase();
+        // Eine kurze Textdatei initialisiert LiteDB stillschweigend als neue, leere Datenbank
+        // (kleiner als eine Seite) — erst genug Datenmüll jenseits der Seitengröße lässt das
+        // Datei-Layout tatsächlich fehlschlagen und simuliert eine echte Beschädigung
+        // (z.B. durch einen vollen Datenträger während der Backup-Kopie).
+        File.WriteAllBytes(temp.Path, Enumerable.Repeat((byte)0x42, 32_768).ToArray());
+        var service = new DatabaseEncryptionService();
+
+        Assert.False(service.CanOpenAndRead(temp.Path, null));
+    }
+
     private sealed class TempDatabase : IDisposable
     {
         private readonly string _directory = System.IO.Path.Combine(

LehrerApp.Data.Tests/RepositoryTests.cs

@@ -1053,6 +1053,101 @@ public sealed class RepositoryTests
         Assert.Equal("fahrt", repo.GetByExternalId("fahrt")!.ExternalId);
     }
 
+    // ── UntisAbsenceCacheRepository / UntisClassRegisterCacheRepository / UntisCacheFetchStateRepository ──
+
+    [Fact]
+    public void UntisAbsenceCacheRepository_GetByClassAndRange_FiltertKlasseUndDatumsbereich()
+    {
+        using var db = NewInMemoryContext();
+        var repo = new UntisAbsenceCacheRepository(db);
+        repo.InsertRange(
+        [
+            new UntisAbsenceCacheEntry { ClassName = "10c", StudentName = "Max", Date = 20260824 },
+            new UntisAbsenceCacheEntry { ClassName = "10c", StudentName = "Max", Date = 20260901 },
+            new UntisAbsenceCacheEntry { ClassName = "10d", StudentName = "Ben", Date = 20260824 },
+        ]);
+
+        var result = repo.GetByClassAndRange("10c", 20260801, 20260831);
+
+        Assert.Single(result);
+        Assert.Equal(20260824, result[0].Date);
+    }
+
+    [Fact]
+    public void UntisAbsenceCacheRepository_ReplaceRange_ErsetztNurDenAngegebenenBereich()
+    {
+        using var db = NewInMemoryContext();
+        var repo = new UntisAbsenceCacheRepository(db);
+        repo.InsertRange(
+        [
+            new UntisAbsenceCacheEntry { ClassName = "10c", StudentName = "Alt", Date = 20260810 },
+            new UntisAbsenceCacheEntry { ClassName = "10c", StudentName = "Alt", Date = 20260901 },
+        ]);
+
+        repo.ReplaceRange("10c", 20260801, 20260831,
+            [new UntisAbsenceCacheEntry { ClassName = "10c", StudentName = "Neu", Date = 20260815 }]);
+
+        var inRange = repo.GetByClassAndRange("10c", 20260801, 20260831);
+        var untouched = repo.GetByClassAndRange("10c", 20260901, 20260901);
+        Assert.Equal("Neu", Assert.Single(inRange).StudentName);
+        Assert.Single(untouched);
+    }
+
+    [Fact]
+    public void UntisClassRegisterCacheRepository_InsertUndGetByClassAndRange_RoundTrip()
+    {
+        using var db = NewInMemoryContext();
+        var repo = new UntisClassRegisterCacheRepository(db);
+        repo.InsertRange([new UntisClassRegisterCacheEntry
+        {
+            ClassName = "10c", Date = 20260824, StudentName = "Max", Subject = "Deu",
+            TeacherUsername = "mueller", CategoryName = "Positiv",
+        }]);
+
+        var result = Assert.Single(repo.GetByClassAndRange("10c", 20260801, 20260831));
+        Assert.Equal("mueller", result.TeacherUsername);
+    }
+
+    [Fact]
+    public void UntisStudentRosterCacheRepository_ReplaceAll_ErsetztNurDieAngegebeneKlasse()
+    {
+        using var db = NewInMemoryContext();
+        var repo = new UntisStudentRosterCacheRepository(db);
+        repo.ReplaceAll("10c", [new UntisStudentRosterCacheEntry { ClassName = "10c", DisplayName = "Alt" }]);
+        repo.ReplaceAll("10d", [new UntisStudentRosterCacheEntry { ClassName = "10d", DisplayName = "Andere Klasse" }]);
+
+        repo.ReplaceAll("10c", [new UntisStudentRosterCacheEntry { ClassName = "10c", DisplayName = "Neu", ExternKey = 42 }]);
+
+        var tenC = repo.GetByClass("10c");
+        var tenD = repo.GetByClass("10d");
+        Assert.Equal("Neu", Assert.Single(tenC).DisplayName);
+        Assert.Equal(42, tenC[0].ExternKey);
+        Assert.Single(tenD); // andere Klasse bleibt unberührt
+    }
+
+    [Fact]
+    public void UntisCacheFetchStateRepository_SaveUndGet_RoundTripJeKlasseUndArt()
+    {
+        using var db = NewInMemoryContext();
+        var repo = new UntisCacheFetchStateRepository(db);
+        var fetchedAt = new DateTime(2026, 8, 25, 10, 0, 0, DateTimeKind.Utc);
+        repo.Save(new UntisCacheFetchState
+        {
+            ClassName = "10c", Kind = UntisCacheKind.Absences,
+            HotWindowFetchedAt = fetchedAt, ColdCoverageStartDate = 20260101,
+        });
+
+        var result = repo.Get("10c", UntisCacheKind.Absences);
+        var missing = repo.Get("10c", UntisCacheKind.ClassRegister);
+
+        Assert.NotNull(result);
+        // LiteDB rundet Kind Utc->Local, verschiebt dabei die Ticks um denselben Zeitpunkt zu
+        // erhalten (siehe CLAUDE.md) - deshalb erst beide Seiten auf UTC normalisieren.
+        Assert.Equal(fetchedAt.ToUniversalTime(), result!.HotWindowFetchedAt!.Value.ToUniversalTime());
+        Assert.Equal(20260101, result.ColdCoverageStartDate);
+        Assert.Null(missing);
+    }
+
     // ── WorkTaskRepository ────────────────────────────────────────────────────
 
     [Fact]

LehrerApp.Data/DatabaseEncryptionService.cs

@@ -37,6 +37,29 @@ public class DatabaseEncryptionService
         }
     }
 
+    /// Öffnet die Datei probeweise und liest die Sammlungsliste, um eine strukturell gültige
+    /// (nicht nur vorhandene) LiteDB-Datei zu bestätigen — z.B. direkt nach dem Anlegen eines
+    /// Backups, das durch einen vollen Datenträger oder einen vorzeitig entfernten USB-Stick
+    /// beschädigt worden sein könnte. Bewusst breites Catch: jede Art von Fehlschlag beim Öffnen
+    /// oder Lesen bedeutet hier "Backup nicht verifizierbar", nicht nur ein falsches Passwort.
+    public bool CanOpenAndRead(string dbPath, string? password)
+    {
+        if (!File.Exists(dbPath)) return false;
+        try
+        {
+            var connection = password is null
+                ? new ConnectionString(dbPath)
+                : new ConnectionString(dbPath) { Password = password };
+            using var db = new LiteDatabase(connection);
+            _ = db.GetCollectionNames().ToList();
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
     /// Setzt (newPassword != null), ändert oder entfernt (newPassword == null) das
     /// Passwort der Datenbank. Der Aufrufer muss sicherstellen, dass keine andere
     /// Verbindung (z.B. der laufende <see cref="LiteDbContext"/>) die Datei offen hält.

LehrerApp.Data/LiteDbContext.cs

@@ -68,6 +68,10 @@ public class LiteDbContext : IDisposable
     public ILiteCollection<SubstitutionEntry> SubstitutionEntries => _db.GetCollection<SubstitutionEntry>("substitution_entries");
     public ILiteCollection<UntisSnapshotEntry> UntisSnapshotEntries => _db.GetCollection<UntisSnapshotEntry>("untis_snapshot_entries");
     public ILiteCollection<UntisSlotMapping> UntisSlotMappings => _db.GetCollection<UntisSlotMapping>("untis_slot_mappings");
+    public ILiteCollection<UntisAbsenceCacheEntry> UntisAbsenceCache => _db.GetCollection<UntisAbsenceCacheEntry>("untis_absence_cache");
+    public ILiteCollection<UntisClassRegisterCacheEntry> UntisClassRegisterCache => _db.GetCollection<UntisClassRegisterCacheEntry>("untis_classregister_cache");
+    public ILiteCollection<UntisCacheFetchState> UntisCacheFetchStates => _db.GetCollection<UntisCacheFetchState>("untis_cache_fetch_state");
+    public ILiteCollection<UntisStudentRosterCacheEntry> UntisStudentRosterCache => _db.GetCollection<UntisStudentRosterCacheEntry>("untis_student_roster_cache");
     public ILiteCollection<AnnualPlanEvent> AnnualPlanEvents => _db.GetCollection<AnnualPlanEvent>("annual_plan_events");
     public ILiteCollection<TrashedItem>    TrashedItems    => _db.GetCollection<TrashedItem>("trash");
 
@@ -535,6 +539,13 @@ public class LiteDbContext : IDisposable
         AnnualPlanEvents.EnsureIndex(x => x.ExternalId, unique: true);
         AnnualPlanEvents.EnsureIndex(x => x.StartDate);
         AnnualPlanEvents.EnsureIndex(x => x.EndDate);
+        UntisAbsenceCache.EnsureIndex(x => x.ClassName);
+        UntisAbsenceCache.EnsureIndex(x => x.Date);
+        UntisClassRegisterCache.EnsureIndex(x => x.ClassName);
+        UntisClassRegisterCache.EnsureIndex(x => x.Date);
+        UntisStudentRosterCache.EnsureIndex(x => x.ClassName);
+        UntisCacheFetchStates.EnsureIndex("ux_class_kind",
+            BsonExpression.Create("STRING($.ClassName) + ':' + STRING($.Kind)"), unique: true);
     }
 
     public void Dispose() => _db.Dispose();

LehrerApp.Data/Repositories/AllRepositories.cs

@@ -492,6 +492,7 @@ public class ParticipationSessionRepository(LiteDbContext db) : IParticipationSe
     public List<ParticipationSession> GetByGroup(Guid groupId) =>
         db.ParticipationSessions.Find(s => s.GroupId == groupId).OrderByDescending(s => s.Date).ToList();
     public ParticipationSession? GetById(Guid id) => db.ParticipationSessions.FindById(id);
+    public List<ParticipationSession> GetAll() => db.ParticipationSessions.FindAll().ToList();
     public void Save(ParticipationSession s)
     {
         ArchivedGroupWriteGuard.EnsureActive(db, s.GroupId);
@@ -794,6 +795,65 @@ public class AnnualPlanEventRepository(LiteDbContext db) : IAnnualPlanEventRepos
     public void Delete(Guid id) => db.AnnualPlanEvents.Delete(id);
 }
 
+// Wie UntisSnapshotEntry/AnnualPlanEvent rein lokal, bewusst kein db.OnChange: Fehlzeiten- und
+// Klassenbuch-Cache fürs Klassenlehrer-Feature (siehe TODO.md) wachsen über ein Schuljahr auf viele
+// hundert Zeilen an - über Sync würde das nur Rauschen erzeugen, und jedes Gerät ruft WebUntis
+// ohnehin selbst ab (siehe UntisReportCacheService).
+public class UntisAbsenceCacheRepository(LiteDbContext db) : IUntisAbsenceCacheRepository
+{
+    public List<UntisAbsenceCacheEntry> GetByClassAndRange(string className, int startDate, int endDate) =>
+        db.UntisAbsenceCache
+          .Find(e => e.ClassName == className && e.Date >= startDate && e.Date <= endDate)
+          .ToList();
+
+    public void ReplaceRange(string className, int startDate, int endDate, IEnumerable<UntisAbsenceCacheEntry> entries)
+    {
+        db.UntisAbsenceCache.DeleteMany(e => e.ClassName == className && e.Date >= startDate && e.Date <= endDate);
+        db.UntisAbsenceCache.InsertBulk(entries);
+    }
+
+    public void InsertRange(IEnumerable<UntisAbsenceCacheEntry> entries) => db.UntisAbsenceCache.InsertBulk(entries);
+}
+
+public class UntisClassRegisterCacheRepository(LiteDbContext db) : IUntisClassRegisterCacheRepository
+{
+    public List<UntisClassRegisterCacheEntry> GetByClassAndRange(string className, int startDate, int endDate) =>
+        db.UntisClassRegisterCache
+          .Find(e => e.ClassName == className && e.Date >= startDate && e.Date <= endDate)
+          .ToList();
+
+    public void ReplaceRange(string className, int startDate, int endDate, IEnumerable<UntisClassRegisterCacheEntry> entries)
+    {
+        db.UntisClassRegisterCache.DeleteMany(e => e.ClassName == className && e.Date >= startDate && e.Date <= endDate);
+        db.UntisClassRegisterCache.InsertBulk(entries);
+    }
+
+    public void InsertRange(IEnumerable<UntisClassRegisterCacheEntry> entries) => db.UntisClassRegisterCache.InsertBulk(entries);
+}
+
+// Gleiches "bewusst kein db.OnChange"-Prinzip wie UntisAbsenceCacheRepository oben, auch wenn der
+// Roster selbst klein bleibt (aktuelle Klassenliste, keine Historie) - jedes Gerät ruft ihn ohnehin
+// selbst ab.
+public class UntisStudentRosterCacheRepository(LiteDbContext db) : IUntisStudentRosterCacheRepository
+{
+    public List<UntisStudentRosterCacheEntry> GetByClass(string className) =>
+        db.UntisStudentRosterCache.Find(e => e.ClassName == className).ToList();
+
+    public void ReplaceAll(string className, IEnumerable<UntisStudentRosterCacheEntry> entries)
+    {
+        db.UntisStudentRosterCache.DeleteMany(e => e.ClassName == className);
+        db.UntisStudentRosterCache.InsertBulk(entries);
+    }
+}
+
+public class UntisCacheFetchStateRepository(LiteDbContext db) : IUntisCacheFetchStateRepository
+{
+    public UntisCacheFetchState? Get(string className, UntisCacheKind kind) =>
+        db.UntisCacheFetchStates.FindOne(s => s.ClassName == className && s.Kind == kind);
+
+    public void Save(UntisCacheFetchState state) => db.UntisCacheFetchStates.Upsert(state);
+}
+
 public class CompetencyDomainRepository(LiteDbContext db) : ICompetencyDomainRepository
 {
     public List<CompetencyDomain> GetBySubjectAndGrade(Guid subjectId, int gradeLevel) =>

LehrerApp.Desktop.Tests/ClassTeacherViewModelsTests.cs

@@ -0,0 +1,587 @@
+using LehrerApp.Core.Models;
+using LehrerApp.Desktop.Services;
+using LehrerApp.Desktop.ViewModels.ClassTeacher;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class ClassTeacherViewModelsTests
+{
+    [Fact]
+    public void GroupByStudentAndDay_FasstFehlstundenProSchuelerUndTagZusammen()
+    {
+        var entries = new[]
+        {
+            new UntisClassAbsenceEntryDto("Muster Max", 1, "6a", 20260824, 1, 45, "HED", "Che", "Absent",
+                "Krank", 1, "24.08.26", true, null, 3, "nicht entsch.", false),
+            new UntisClassAbsenceEntryDto("Muster Max", 1, "6a", 20260824, 1, 45, "PAN", "Kunst", null,
+                "Krank", 2, "24.08.26", true, null, 5, "nicht entsch.", true),
+            new UntisClassAbsenceEntryDto("Andere Schuelerin", 2, "6a", 20260824, 1, 20, "BEN", "Deu",
+                "Verspätung", null, 3, "24.08.26", false, "Zug verpasst", 1, "entsch.", false),
+        };
+
+        var rows = ClassAbsenceDaySummaryRow.GroupByStudentAndDay(entries);
+
+        Assert.Equal(2, rows.Count);
+
+        var max = rows[1];
+        Assert.Equal("Muster Max", max.StudentName);
+        Assert.Equal(2, max.TotalAbsentPeriods);
+        Assert.Equal(90, max.TotalAbsentMinutes);
+        Assert.Equal(["Che", "Kunst"], max.Subjects);
+        Assert.Equal([3, 5], max.PeriodNumbers.Order());
+        Assert.Equal(["nicht entsch."], max.Statuses);
+        Assert.Equal(["Absent"], max.AbsenceReasons);
+        Assert.Equal("Krank", max.Note);
+        Assert.Null(max.ExcuseNote);
+        Assert.True(max.CountsAsFullDay);
+
+        var andere = rows[0];
+        Assert.Equal("Andere Schuelerin", andere.StudentName);
+        Assert.Equal(1, andere.TotalAbsentPeriods);
+        Assert.Equal(20, andere.TotalAbsentMinutes);
+        Assert.Equal(["Deu"], andere.Subjects);
+        Assert.Null(andere.Note);
+        Assert.Equal("Zug verpasst", andere.ExcuseNote);
+        Assert.False(andere.CountsAsFullDay);
+    }
+
+    [Fact]
+    public void GroupByStudentAndDay_TrenntGleichenNamenAnUnterschiedlichenTagen()
+    {
+        var entries = new[]
+        {
+            new UntisClassAbsenceEntryDto("Muster Max", 1, "6a", 20260824, 1, 45, "HED", "Che", null,
+                null, 1, "24.08.26", true, null, 3, "nicht entsch.", false),
+            new UntisClassAbsenceEntryDto("Muster Max", 1, "6a", 20260825, 1, 45, "HED", "Che", null,
+                null, 2, "25.08.26", true, null, 3, "nicht entsch.", false),
+        };
+
+        var rows = ClassAbsenceDaySummaryRow.GroupByStudentAndDay(entries);
+
+        Assert.Equal(2, rows.Count);
+        Assert.Equal(new DateOnly(2026, 8, 25), rows[0].Date);
+        Assert.Equal(new DateOnly(2026, 8, 24), rows[1].Date);
+    }
+
+    [Fact]
+    public void RosterBuild_OrdnetFehlzeitPerExternKeyUndKlassenbuchPerNameZu()
+    {
+        var students = new[]
+        {
+            Student(1001, "Ada Müller"),
+            Student(1002, "Ben Schmidt"),
+            Student(1003, "Cem Yilmaz"),
+        };
+        var todayAbsences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 25), "Ada Müller", 1001, 2, 90,
+                ["Che"], [3, 4], ["nicht entsch."], ["Absent"], null, null, false),
+        };
+        var recentClassRegister = new[]
+        {
+            new UntisForeignClassRegisterEventDto("6a", 20260824, "Deu", "Ben Schmidt", "mueller",
+                "Vergessen", "Organisation", "Buch vergessen"),
+        };
+
+        var roster = ClassTeacherRosterRow.Build(students, todayAbsences, recentClassRegister);
+
+        Assert.Equal(3, roster.Count);
+        var ada = Assert.Single(roster, r => r.StudentName == "Ada Müller");
+        Assert.True(ada.HasAbsenceToday);
+        Assert.Contains("nicht entsch.", ada.AbsenceTooltip);
+        Assert.False(ada.HasRecentClassRegisterEntry);
+
+        var ben = Assert.Single(roster, r => r.StudentName == "Ben Schmidt");
+        Assert.False(ben.HasAbsenceToday);
+        Assert.True(ben.HasRecentClassRegisterEntry);
+
+        var cem = Assert.Single(roster, r => r.StudentName == "Cem Yilmaz");
+        Assert.False(cem.HasAbsenceToday);
+        Assert.False(cem.HasRecentClassRegisterEntry);
+    }
+
+    [Fact]
+    public void RosterBuild_ErkenntNamenAuchInVertauschterReihenfolge()
+    {
+        // WebUntis liefert Namen im Schülerreport als "Vorname Nachname", in Fehlzeiten-/
+        // Klassenbuchberichten aber typischerweise als "Nachname Vorname" - der Namensabgleich
+        // muss das auch ohne ExternKey erkennen (Regressionstest für genau diesen Bug).
+        var students = new[] { Student(externKey: null, displayName: "Ben Schmidt") };
+        var todayAbsences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 25), "Schmidt Ben", null, 1, 45,
+                ["Che"], [3], ["nicht entsch."], ["Absent"], null, null, false),
+        };
+        var recentClassRegister = new[]
+        {
+            new UntisForeignClassRegisterEventDto("6a", 20260824, "Deu", "Schmidt Ben", "mueller",
+                "Vergessen", "Organisation", "Buch vergessen"),
+        };
+
+        var roster = ClassTeacherRosterRow.Build(students, todayAbsences, recentClassRegister);
+
+        var ben = Assert.Single(roster);
+        Assert.True(ben.HasAbsenceToday);
+        Assert.True(ben.HasRecentClassRegisterEntry);
+    }
+
+    [Fact]
+    public void RosterBuild_BeschreibtVerspaetungNichtAlsNullFehlstunden()
+    {
+        var students = new[] { Student(1001, "Ada Müller") };
+        var todayAbsences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 26), "Müller Ada", 1001, 0, 20,
+                ["Deu"], [1], ["nicht entsch."], ["Verspätung"], null, null, false),
+        };
+
+        var row = Assert.Single(ClassTeacherRosterRow.Build(students, todayAbsences, [],
+            new DateOnly(2026, 8, 26)));
+
+        Assert.True(row.IsLate);
+        Assert.True(row.IsUnexcused);
+        Assert.Equal("20 Min. verspätet · Unentschuldigt", row.StatusText);
+        Assert.Equal(ClassTeacherStatusKind.Danger, row.StatusKind);
+    }
+
+    [Fact]
+    public void RosterBuild_PriorisiertHandlungsbedarfVorUnauffaelligenSchuelern()
+    {
+        var students = new[]
+        {
+            Student(1001, "Zora Unauffällig"),
+            Student(1002, "Ada Fehlzeit"),
+            Student(1003, "Ben Klassenbuch"),
+        };
+        var absences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 26), "Fehlzeit Ada", 1002, 2, 90,
+                ["Deu"], [1, 2], ["nicht entsch."], ["Absent"], null, null, false),
+        };
+        var register = new[]
+        {
+            new UntisForeignClassRegisterEventDto("10c", 20260825, "Deu", "Klassenbuch Ben", "test",
+                "Fehlende HA", "Negativ", "Hausaufgaben fehlen"),
+        };
+
+        var rows = ClassTeacherRosterRow.Build(students, absences, register, new DateOnly(2026, 8, 26));
+
+        Assert.Equal(["Ada Fehlzeit", "Ben Klassenbuch", "Zora Unauffällig"],
+            rows.Select(r => r.StudentName));
+    }
+
+    [Fact]
+    public void RosterBuild_BerechnetFehlquoteSeitSchuljahresbeginn()
+    {
+        var students = new[] { Student(1001, "Ada Müller") };
+        var yearAbsences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 10), "Müller Ada", 1001, 2, 90,
+                ["Che"], [1, 2], ["entsch."], ["Krank"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 17), "Müller Ada", 1001, 6, 270,
+                ["Che"], [1, 2, 3, 4, 5, 6], ["nicht entsch."], ["Absent"], null, null, true),
+        };
+
+        var row = Assert.Single(ClassTeacherRosterRow.Build(students, [], [],
+            new DateOnly(2026, 8, 26), yearAbsences, schoolDaysElapsed: 20,
+            termStart: new DateOnly(2026, 8, 1)));
+
+        Assert.True(row.HasYearSummary);
+        Assert.Equal(2, row.YearAbsenceDayCount);
+        Assert.Equal(1, row.YearUnexcusedDayCount);
+        Assert.Equal(10, row.YearAbsenceRatePercent);
+        Assert.Contains("10 %", row.YearSummaryLabel);
+        Assert.Contains("2 von 20", row.YearSummaryTooltip);
+        Assert.Contains("seit 01.08.", row.YearSummaryTooltip);
+        Assert.Contains("1 unentschuldigt", row.YearSummaryTooltip);
+    }
+
+    [Fact]
+    public void RosterBuild_ZeigtAbgezogeneFerientageImTooltip()
+    {
+        // Nutzer-Nachfrage: die Herkunft des Nenners soll sich ohne Blick in die WebUntis-Ferienliste
+        // direkt in der App nachvollziehen lassen, nachdem er zeitweise Ferientage mitzählte.
+        var students = new[] { Student(1001, "Ada Müller") };
+        var yearAbsences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 17), "Müller Ada", 1001, 2, 90,
+                ["Che"], [1, 2], ["entsch."], ["Krank"], null, null, false),
+        };
+
+        var row = Assert.Single(ClassTeacherRosterRow.Build(students, [], [],
+            new DateOnly(2026, 8, 26), yearAbsences, schoolDaysElapsed: 14, holidayWeekdaysExcluded: 7,
+            termStart: new DateOnly(2026, 8, 1)));
+
+        Assert.Contains("7 Ferientage abgezogen", row.YearSummaryTooltip);
+    }
+
+    [Fact]
+    public void RosterBuild_OhneJahresdatenZeigtKeineFehlquote()
+    {
+        var students = new[] { Student(1001, "Ada Müller") };
+
+        var row = Assert.Single(ClassTeacherRosterRow.Build(students, [], [], new DateOnly(2026, 8, 26)));
+
+        Assert.False(row.HasYearSummary);
+        Assert.Equal("", row.YearSummaryLabel);
+        Assert.Null(row.YearSummaryTooltip);
+    }
+
+    [Fact]
+    public void RosterBuild_OrdnetJahresfehlzeitenAuchOhneExternKeyUeberNamenZu()
+    {
+        var students = new[] { Student(externKey: null, displayName: "Ben Schmidt") };
+        var yearAbsences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 10), "Schmidt Ben", null, 2, 90,
+                ["Che"], [1, 2], ["entsch."], ["Krank"], null, null, false),
+        };
+
+        var row = Assert.Single(ClassTeacherRosterRow.Build(students, [], [], new DateOnly(2026, 8, 26),
+            yearAbsences, schoolDaysElapsed: 10));
+
+        Assert.Equal(1, row.YearAbsenceDayCount);
+    }
+
+    [Fact]
+    public void TrendDay_AnteileSummierenSichZurGesamtquote()
+    {
+        var day = new ClassTeacherTrendDay("Mo", 5, 2, 1, 2, 0.4d, 0.2d, 0.4d);
+
+        Assert.Equal(1.0d, day.TotalFraction, precision: 10);
+    }
+
+    [Fact]
+    public void RosterBuild_StelltGefahrUndWarnungMitSymbolVoran()
+    {
+        var students = new[] { Student(1001, "Ada Müller"), Student(1002, "Ben Schmidt") };
+        var todayAbsences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 26), "Müller Ada", 1001, 2, 90,
+                ["Che"], [1, 2], ["nicht entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 26), "Schmidt Ben", 1002, 2, 90,
+                ["Che"], [1, 2], ["entsch."], ["Absent"], null, null, false),
+        };
+
+        var roster = ClassTeacherRosterRow.Build(students, todayAbsences, [], new DateOnly(2026, 8, 26));
+
+        var ada = Assert.Single(roster, r => r.StudentName == "Ada Müller");
+        Assert.Equal(ClassTeacherStatusKind.Danger, ada.StatusKind);
+        Assert.StartsWith("✕ ", ada.StatusTextWithGlyph);
+
+        var ben = Assert.Single(roster, r => r.StudentName == "Ben Schmidt");
+        Assert.Equal(ClassTeacherStatusKind.Warning, ben.StatusKind);
+        Assert.StartsWith("△ ", ben.StatusTextWithGlyph);
+    }
+
+    [Fact]
+    public void RosterBuild_LaesstUnauffaelligenStatusOhneSymbol()
+    {
+        var students = new[] { Student(1001, "Zora Unauffällig") };
+
+        var row = Assert.Single(ClassTeacherRosterRow.Build(students, [], [], new DateOnly(2026, 8, 26)));
+
+        Assert.Equal(row.StatusText, row.StatusTextWithGlyph);
+    }
+
+    // ── Nenner der Jahresfehlquote: echter WebUntis-Ferienkalender statt grober Werktagszählung ──
+
+    [Fact]
+    public void CountSchoolWeekdays_SchliesstFerientageAus()
+    {
+        // 1.-31.08.2026 hat 21 Werktage; die (fiktiven) Sommerferien bis 11.08. nehmen davon 7
+        // Werktage weg (Mo 03. - Fr 07., Mo 10. - Di 11.) - Nutzer-Feedback: Schüler, die seit
+        // Unterrichtsbeginn jeden Tag fehlten, kamen wegen dieser mitgezählten Ferienzeit nur auf
+        // ~57 % statt ~100 % Fehlquote.
+        var holidays = new[] { new CachedUntisHoliday("Sommerferien", new DateOnly(2026, 7, 1), new DateOnly(2026, 8, 11)) };
+
+        var schoolDays = ClassTeacherOverviewViewModel.CountSchoolWeekdays(
+            new DateOnly(2026, 8, 1), new DateOnly(2026, 8, 31), holidays);
+
+        Assert.Equal(14, schoolDays);
+    }
+
+    [Fact]
+    public void CountSchoolWeekdays_OhneFerienVerhaeltSichWieReineWerktagszaehlung()
+    {
+        var schoolDays = ClassTeacherOverviewViewModel.CountSchoolWeekdays(
+            new DateOnly(2026, 8, 1), new DateOnly(2026, 8, 31), []);
+
+        Assert.Equal(21, schoolDays);
+    }
+
+    [Fact]
+    public void EstimateTermStart_NutztFruehestenFehlzeitEintragDerGanzenKlasse()
+    {
+        // Realer Befund (Nutzer-Feedback): WebUntis' getHolidays liefert für Bremen nie einen
+        // Sommerferien-Eintrag (über 11 Jahre Kontohistorie geprüft, kein einziger Juli-/August-
+        // Zeitraum dabei) - vermutlich weil die Sommerferien WebUntis-intern zwischen zwei
+        // Schuljahres-Datensätzen liegen (1.8./31.7.-Grenze), nicht "in" einem davon. Für den
+        // Schuljahresbeginn bleibt deshalb weiterhin der früheste Fehlzeiten-Eintrag der Klasse
+        // nötig statt CountSchoolWeekdays allein.
+        var absences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 13), "Fehlt Cem", 1001, 1, 45,
+                ["Deu"], [1], ["nicht entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 19), "Andere Ada", 1002, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+        };
+
+        var termStart = ClassTeacherOverviewViewModel.EstimateTermStart(absences, new DateOnly(2026, 8, 1));
+
+        Assert.Equal(new DateOnly(2026, 8, 13), termStart);
+    }
+
+    [Fact]
+    public void EstimateTermStart_FaelltOhneFehlzeitenAufSchuljahresbeginnZurueck()
+    {
+        var termStart = ClassTeacherOverviewViewModel.EstimateTermStart([], new DateOnly(2026, 8, 1));
+
+        Assert.Equal(new DateOnly(2026, 8, 1), termStart);
+    }
+
+    [Fact]
+    public void CountSchoolWeekdays_AbEchtemTerminstartOhneSommerferienEintragStimmtMitBeobachtungUeberein()
+    {
+        // Regressionstest für den konkret gemeldeten Fall: 13 tatsächliche Schultage seit
+        // Unterrichtsbeginn (13.08.2026, ein Donnerstag) bis 31.08.2026, keine WebUntis-Ferien im
+        // Bereich (die nächste, "Herbstferien", liegt erst im Oktober) - Kombination aus
+        // EstimateTermStart (Sommerferien-Lücke) und CountSchoolWeekdays (übrige Ferien) muss auf
+        // die vom Nutzer nachgezählte Zahl kommen, nicht auf die volle Werktagszahl ab 1.8. (21).
+        var termStart = new DateOnly(2026, 8, 13);
+        var noHolidaysInRange = Array.Empty<CachedUntisHoliday>();
+
+        var schoolDays = ClassTeacherOverviewViewModel.CountSchoolWeekdays(
+            termStart, new DateOnly(2026, 8, 31), noHolidaysInRange);
+
+        Assert.Equal(13, schoolDays);
+    }
+
+    // ── Offene Entschuldigungen (Feature-Idee 2) ─────────────────────────────
+
+    [Fact]
+    public void OpenExcuseBuild_SortiertNachTagenOffenAbsteigendUndIgnoriertEntschuldigte()
+    {
+        var absences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 20), "Alt Ada", 1001, 2, 90,
+                ["Che"], [1, 2], ["nicht entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 25), "Neu Ben", 1002, 1, 45,
+                ["Deu"], [1], ["nicht entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 24), "Entschuldigt Cem", 1003, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+        };
+
+        var rows = ClassTeacherOpenExcuseRow.Build(absences, new DateOnly(2026, 8, 26));
+
+        // StudentName kommt aus StudentDisplayName (WebUntis liefert "Nachname Vorname",
+        // hier für die Anzeige auf "Vorname Nachname" gedreht - siehe ClassAbsenceDaySummaryRow).
+        Assert.Equal(["Ada Alt", "Ben Neu"], rows.Select(r => r.StudentName));
+        Assert.Equal(6, rows[0].DaysOpen);
+        Assert.True(rows[0].IsOverdue);
+        Assert.Equal(1, rows[1].DaysOpen);
+        Assert.False(rows[1].IsOverdue);
+    }
+
+    [Fact]
+    public void OpenExcuseBuild_IgnoriertUnentschuldigteVerspaetungen()
+    {
+        // Verspätungen sind i.d.R. nicht entschuldigungsfähig - "unentschuldigt" darf hier keine
+        // Erinnerung an eine fehlende Entschuldigung auslösen (Nutzer-Feedback).
+        var absences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 25), "Neu Ben", 1002, 0, 15,
+                ["Deu"], [1], ["nicht entsch."], ["Verspätung"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 24), "Fehlt Cem", 1003, 1, 45,
+                ["Deu"], [1], ["nicht entsch."], ["Absent"], null, null, false),
+        };
+
+        var rows = ClassTeacherOpenExcuseRow.Build(absences, new DateOnly(2026, 8, 26));
+
+        Assert.Equal(["Cem Fehlt"], rows.Select(r => r.StudentName));
+    }
+
+    // ── Verspätungsmuster: Elterngespräch-Eskalation (Nutzer-Feedback) ───────
+
+    [Fact]
+    public void DetectLatePatterns_EskaliertBeiHoherJahressummeMitWiedervorlageOption()
+    {
+        var absences = Enumerable.Range(0, 5)
+            .Select(i => new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 3 + i), "Spaet Timo", 1001, 0, 10,
+                ["Deu"], [1], ["entsch."], ["Verspätung"], null, null, false))
+            .ToArray();
+        var names = new Dictionary<string, string> { [UntisNameMatching.NameKey("Spaet Timo")] = "Timo Spät" };
+
+        var notices = ClassTeacherOverviewViewModel.DetectLatePatterns(
+            absences, names, sevenDayStart: new DateOnly(2026, 8, 31));
+
+        var notice = Assert.Single(notices);
+        Assert.Equal("Timo Spät", notice.StudentName);
+        Assert.Contains("5 Verspätungen seit Schuljahresbeginn", notice.Message);
+        Assert.Equal(ClassTeacherStatusKind.Danger, notice.Kind);
+        Assert.True(notice.CanCreateReminder);
+    }
+
+    [Fact]
+    public void DetectLatePatterns_KurzfristigesClusterBleibtHinweisOhneAktion()
+    {
+        var absences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 24), "Spaet Timo", 1001, 0, 10,
+                ["Deu"], [1], ["entsch."], ["Verspätung"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 25), "Spaet Timo", 1001, 0, 10,
+                ["Deu"], [1], ["entsch."], ["Verspätung"], null, null, false),
+        };
+        var names = new Dictionary<string, string> { [UntisNameMatching.NameKey("Spaet Timo")] = "Timo Spät" };
+
+        var notices = ClassTeacherOverviewViewModel.DetectLatePatterns(
+            absences, names, sevenDayStart: new DateOnly(2026, 8, 20));
+
+        var notice = Assert.Single(notices);
+        Assert.Equal("2-mal verspätet in 7 Tagen", notice.Message);
+        Assert.Equal(ClassTeacherStatusKind.Warning, notice.Kind);
+        Assert.False(notice.CanCreateReminder);
+    }
+
+    [Fact]
+    public void DetectLatePatterns_UnentschuldigteFehltageGehenVorVerspaetungseskalation()
+    {
+        var absences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 24), "Fehlt Cem", 1001, 1, 45,
+                ["Deu"], [1], ["nicht entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 25), "Fehlt Cem", 1001, 1, 45,
+                ["Deu"], [1], ["nicht entsch."], ["Absent"], null, null, false),
+        };
+        var names = new Dictionary<string, string> { [UntisNameMatching.NameKey("Fehlt Cem")] = "Cem Fehlt" };
+
+        var notices = ClassTeacherOverviewViewModel.DetectLatePatterns(
+            absences, names, sevenDayStart: new DateOnly(2026, 8, 20));
+
+        var notice = Assert.Single(notices);
+        Assert.Contains("unentschuldigte Fehltage", notice.Message);
+        Assert.Equal(ClassTeacherStatusKind.Danger, notice.Kind);
+        Assert.False(notice.CanCreateReminder);
+    }
+
+    // ── Aggregierte Klassenbuch-Kategorien (Feature-Idee 5) ──────────────────
+
+    [Fact]
+    public void CategoryAggregateBuild_ZaehltProKategorieUndNenntTopSchueler()
+    {
+        var entries = new[]
+        {
+            new ClassTeacherClassRegisterRow(new DateOnly(2026, 8, 20), "Deu", "Schmidt Ben", "test",
+                "Hausaufgaben fehlen", "Negativ", "HA fehlt"),
+            new ClassTeacherClassRegisterRow(new DateOnly(2026, 8, 21), "Deu", "Schmidt Ben", "test",
+                "Hausaufgaben fehlen", "Negativ", "HA fehlt"),
+            new ClassTeacherClassRegisterRow(new DateOnly(2026, 8, 22), "Che", "Müller Ada", "test",
+                "Hausaufgaben fehlen", "Negativ", "HA fehlt"),
+            new ClassTeacherClassRegisterRow(new DateOnly(2026, 8, 23), "Che", "Müller Ada", "test",
+                "Lob", "Positiv", "Gute Mitarbeit"),
+        };
+
+        var rows = ClassTeacherCategoryAggregateRow.Build(entries);
+
+        Assert.Equal(["Hausaufgaben fehlen", "Lob"], rows.Select(r => r.CategoryName));
+        var homework = rows[0];
+        Assert.Equal(3, homework.Count);
+        Assert.Contains("2× Ben Schmidt", homework.TopStudentsLabel);
+        Assert.Contains("1× Ada Müller", homework.TopStudentsLabel);
+    }
+
+    // ── Erweiterte Mustererkennung: Wochentags-Häufung (Feature-Idee 4) ──────
+
+    [Fact]
+    public void DetectWeekdayPatterns_ErkenntDeutlicheHaeufungAnEinemWochentag()
+    {
+        // 24.08./31.08.2026 und 07.09.2026 sind allesamt Montage.
+        var absences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 24), "Muster Mona", 1001, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 31), "Muster Mona", 1001, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 9, 7), "Muster Mona", 1001, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+        };
+        var names = new Dictionary<string, string> { [UntisNameMatching.NameKey("Muster Mona")] = "Mona Muster" };
+
+        var notices = ClassTeacherOverviewViewModel.DetectWeekdayPatterns(
+            absences, names, new HashSet<string>());
+
+        var notice = Assert.Single(notices);
+        Assert.Equal("Mona Muster", notice.StudentName);
+        Assert.Contains("Montag", notice.Message);
+        Assert.Equal(ClassTeacherStatusKind.Info, notice.Kind);
+    }
+
+    [Fact]
+    public void DetectWeekdayPatterns_IgnoriertZuKleineStichprobe()
+    {
+        var absences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 24), "Muster Mona", 1001, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 31), "Muster Mona", 1001, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+        };
+
+        var notices = ClassTeacherOverviewViewModel.DetectWeekdayPatterns(
+            absences, new Dictionary<string, string>(), new HashSet<string>());
+
+        Assert.Empty(notices);
+    }
+
+    [Fact]
+    public void DetectWeekdayPatterns_LaesstBereitsGemeldeteSchuelerAus()
+    {
+        var absences = new[]
+        {
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 24), "Muster Mona", 1001, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 8, 31), "Muster Mona", 1001, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+            new ClassAbsenceDaySummaryRow(new DateOnly(2026, 9, 7), "Muster Mona", 1001, 1, 45,
+                ["Deu"], [1], ["entsch."], ["Absent"], null, null, false),
+        };
+        var names = new Dictionary<string, string> { [UntisNameMatching.NameKey("Muster Mona")] = "Mona Muster" };
+
+        var notices = ClassTeacherOverviewViewModel.DetectWeekdayPatterns(
+            absences, names, new HashSet<string> { "Mona Muster" });
+
+        Assert.Empty(notices);
+    }
+
+    // ── Noten-/Mitarbeit-Brücke: Namensabgleich (Feature-Idee 7) ─────────────
+
+    [Fact]
+    public void MatchStudent_FindetUeberVorUndNachnameTrotzKommaInFullName()
+    {
+        // Student.FullName liefert "Nachname, Vorname" (mit Komma) - ein Abgleich darüber würde
+        // UntisNameMatching.NameKey verfälschen ("Müller," bliebe eigenes Wort). MatchStudent
+        // muss deshalb FirstName/LastName getrennt verwenden, nicht FullName.
+        var students = new List<Student>
+        {
+            new() { FirstName = "Ada", LastName = "Müller" },
+            new() { FirstName = "Ben", LastName = "Schmidt" },
+        };
+
+        var match = ClassTeacherOverviewViewModel.MatchStudent("Müller Ada", students);
+
+        Assert.NotNull(match);
+        Assert.Equal("Ada", match!.FirstName);
+    }
+
+    [Fact]
+    public void MatchStudent_LiefertNullOhneTreffer()
+    {
+        var students = new List<Student> { new() { FirstName = "Ada", LastName = "Müller" } };
+
+        Assert.Null(ClassTeacherOverviewViewModel.MatchStudent("Unbekannt Xyz", students));
+    }
+
+    private static UntisStudentRosterCacheEntry Student(int? externKey, string displayName) =>
+        new() { ClassName = "6a", ExternKey = externKey, DisplayName = displayName };
+}

LehrerApp.Desktop.Tests/CreateLetterDialogViewModelTests.cs

@@ -1,7 +1,6 @@
-using System.IO.Compression;
 using LehrerApp.Core.Models;
-using LehrerApp.Core.Services;
 using LehrerApp.Desktop.ViewModels.Students;
+using LehrerApp.Templating;
 using Xunit;
 
 namespace LehrerApp.Desktop.Tests;
@@ -9,16 +8,12 @@ namespace LehrerApp.Desktop.Tests;
 public sealed class CreateLetterDialogViewModelTests : IDisposable
 {
     private readonly string _directory = Path.Combine(Path.GetTempPath(), $"lehrerapp-letter-vm-tests-{Guid.NewGuid():N}");
-
     public CreateLetterDialogViewModelTests() => Directory.CreateDirectory(_directory);
 
     [Fact]
     public void OhneVorlage_KannKeinenBriefErzeugen()
     {
-        var student = StudentWithContact("Sehr geehrte Frau Muster,");
+        var vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), new TemplateStore(_directory));
-
-        var vm = Build(student, new LetterTemplateService(_directory));
-
         Assert.False(vm.CanGenerate);
         Assert.Contains(vm.Issues, i => i.Message.Contains("Vorlage", StringComparison.OrdinalIgnoreCase));
     }
@@ -26,83 +21,63 @@ public sealed class CreateLetterDialogViewModelTests : IDisposable
     [Fact]
     public void VerwendeteBriefanredeFehlt_BlockiertErzeugung()
     {
-        var service = ServiceWithTemplate("Letter.Salutation");
+        var vm = Build(StudentWithContact(null), StoreWithTemplate(
-        var vm = Build(StudentWithContact(null), service);
+            new PlaceholderDefinition("Anrede", PlaceholderType.Text, true)));
-
         Assert.False(vm.CanGenerate);
-        Assert.Contains(vm.Issues, i => i.Message.Contains("Briefanrede"));
+        Assert.Contains(vm.Issues, i => i.Message.Contains("Anrede", StringComparison.OrdinalIgnoreCase));
     }
 
     [Fact]
-    public void VollstaendigeDaten_ErzeugenEditierbareDocxKopie()
+    public void VollstaendigeDaten_ErzeugenFlachesPdf()
     {
-        var service = ServiceWithTemplate("Letter.Salutation", "Student.FirstName", "CurrentDate");
+        var store = StoreWithTemplate(new PlaceholderDefinition("Anrede", PlaceholderType.Text, true),
-        var vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), service);
+            new PlaceholderDefinition("Datum", PlaceholderType.Date, true),
-        var output = Path.Combine(_directory, "Brief.docx");
+            new PlaceholderDefinition("Brieftext", PlaceholderType.Multiline, true));
+        var vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), store);
+        vm.LetterText = "Dies ist der Inhalt.";
+        var output = Path.Combine(_directory, "Brief.pdf");
 
-        var generated = vm.Generate(output);
+        Assert.True(vm.Generate(output));
-
+        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(output), 0, 4));
-        Assert.True(generated);
-        Assert.True(File.Exists(output));
-        using var archive = ZipFile.OpenRead(output);
-        using var reader = new StreamReader(archive.GetEntry("word/document.xml")!.Open());
-        var xml = reader.ReadToEnd();
-        Assert.Contains("Sehr geehrte Frau Muster,", xml);
-        Assert.Contains("Lena", xml);
     }
 
     [Fact]
-    public void KontaktBearbeiten_SpeichertExpliziteBriefanrede()
+    public void KonstanterPflichttext_BenoetigtKeineExterneEingabe()
     {
-        var vm = new ContactEditDialogViewModel(new Contact { Name = "Frau Muster" });
+        var store = StoreWithTemplate(new PlaceholderDefinition("Brieftext", PlaceholderType.Multiline,
-        vm.LetterSalutation = "Sehr geehrte Frau Muster,";
+            Required: true, IsConstant: true, ConstantValue: "Fest im Vorlagenpaket"));
+        var vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), store);
+        var output = Path.Combine(_directory, "Konstant.pdf");
 
-        vm.SaveCommand.Execute(null);
+        Assert.True(vm.CanGenerate);
-
+        Assert.True(vm.Generate(output));
-        Assert.Equal("Sehr geehrte Frau Muster,", vm.Result!.LetterSalutation);
+        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(output), 0, 4));
     }
 
-    private CreateLetterDialogViewModel Build(Student student, LetterTemplateService service) =>
+    private CreateLetterDialogViewModel Build(Student student, TemplateStore store) =>
-        new(student, service, new FakeMemberships([]), new FakeGroups([]));
+        new(student, store, new QuestTemplateRenderer(), new FakeMemberships([]), new FakeGroups([]));
 
-    private LetterTemplateService ServiceWithTemplate(params string[] tags)
+    private TemplateStore StoreWithTemplate(params PlaceholderDefinition[] definitions)
     {
-        var source = Path.Combine(_directory, $"{Guid.NewGuid():N}.docx");
+        var source = Path.Combine(_directory, $"{Guid.NewGuid():N}.lavorlage");
-        using (var archive = ZipFile.Open(source, ZipArchiveMode.Create))
+        var manifest = new TemplateManifest { Id = $"brief-{Guid.NewGuid():N}", Name = "Elternbrief", Placeholders = [.. definitions] };
+        var lines = new List<string> { "PAGE 210 297 mm" };
+        var y = 20;
+        foreach (var definition in definitions)
         {
-            var entry = archive.CreateEntry("word/document.xml");
+            var element = definition.Type == PlaceholderType.Multiline ? "TEXTBOX" : "TEXT";
-            using var writer = new StreamWriter(entry.Open());
+            lines.Add(element == "TEXTBOX" ? $"TEXTBOX 20 {y} 170 80 ${definition.Name}" : $"TEXT 20 {y} ${definition.Name}");
-            var controls = string.Join("", tags.Select(tag =>
+            y += 20;
-                $"<w:sdt><w:sdtPr><w:tag w:val=\"{tag}\"/></w:sdtPr><w:sdtContent>" +
-                "<w:p><w:r><w:t>Platzhalter</w:t></w:r></w:p></w:sdtContent></w:sdt>"));
-            writer.Write("<w:document xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\">" +
-                         $"<w:body>{controls}</w:body></w:document>");
         }
-        var service = new LetterTemplateService(Path.Combine(_directory, $"service-{Guid.NewGuid():N}"));
+        TemplatePackage.Create(source, manifest, string.Join('\n', lines), new Dictionary<string, byte[]>());
-        service.Import(source, "Elternbrief");
+        var store = new TemplateStore(Path.Combine(_directory, $"store-{Guid.NewGuid():N}")); store.Import(source); return store;
-        return service;
     }
 
     private static Student StudentWithContact(string? salutation) => new()
     {
-        FirstName = "Lena",
+        FirstName = "Lena", LastName = "Beispiel",
-        LastName = "Beispiel",
+        Contacts = [new Contact { Name = "Frau Muster", Relation = "Mutter", LetterSalutation = salutation,
-        Contacts =
+            Street = "Hauptstraße 1", PostalCode = "12345", City = "Musterstadt" }],
-        [
-            new Contact
-            {
-                Name = "Frau Muster",
-                Relation = "Mutter",
-                LetterSalutation = salutation,
-                Street = "Hauptstraße 1",
-                PostalCode = "12345",
-                City = "Musterstadt",
-            },
-        ],
     };
-
+    public void Dispose() { if (Directory.Exists(_directory)) Directory.Delete(_directory, true); }
-    public void Dispose()
-    {
-        if (Directory.Exists(_directory)) Directory.Delete(_directory, recursive: true);
-    }
 }

LehrerApp.Desktop.Tests/DashboardViewModelTests.cs

@@ -1,6 +1,7 @@
 using LehrerApp.Core.Models;
 using LehrerApp.Core.Services;
 using LehrerApp.Desktop.ViewModels;
+using System.Globalization;
 using Xunit;
 
 namespace LehrerApp.Desktop.Tests;
@@ -11,6 +12,22 @@ namespace LehrerApp.Desktop.Tests;
 /// (offene Aufgaben, ...).
 public sealed class DashboardViewModelTests
 {
+    [Fact]
+    public void LeereHinweisbereiche_WerdenAusgeblendetUndZusammenfassungBleibtKompakt()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today });
+
+        Assert.False(vm.ExcusesCard.EffectiveIsVisible);
+        Assert.False(vm.CorrectionsCard.EffectiveIsVisible);
+        Assert.False(vm.AlertsCard.EffectiveIsVisible);
+        Assert.Equal("0 offene Punkte", vm.AttentionSummary);
+        Assert.True(vm.TodayCard.EffectiveIsVisible);
+        Assert.True(vm.CalendarCard.EffectiveIsVisible);
+    }
+
     private static PeriodScheduleService NewPeriodSchedule()
     {
         var tempPath = System.IO.Path.Combine(
@@ -43,12 +60,13 @@ public sealed class DashboardViewModelTests
         DashboardSettingsService? dashboardSettings = null, FakeSchoolHolidays? schoolHolidays = null,
         FakeLessons? lessons = null, FakeSubstitutionEntries? substitutions = null,
         FakeSessions? sessions = null, FakeEntries? entries = null,
-        FakeAnnualPlanEvents? annualPlanEvents = null)
+        FakeAnnualPlanEvents? annualPlanEvents = null, List<LearningGroup>? allGroups = null,
+        FakeTimeEntries? timeEntries = null)
     {
         lessons ??= new FakeLessons();
         lessons.Add(lesson);
         return new DashboardViewModel(
-            new FakeGroups([group]), new FakeSubjects([]), lessons,
+            new FakeGroups(allGroups ?? [group]), new FakeSubjects([]), lessons,
             exams ?? new FakeExams([]), results ?? new FakeResults(), grades ?? new FakeGrades(),
             reportGrades ?? new FakeReportGrades(), memberships ?? new FakeMemberships([]),
             tasks ?? new FakeWorkTasks(), sessions ?? new FakeSessions([]), entries ?? new FakeEntries(),
@@ -56,7 +74,182 @@ public sealed class DashboardViewModelTests
             slots ?? new FakeTimetableSlots(), periodSchedule ?? NewPeriodSchedule(),
             new AttendanceBalanceService(), new SchoolYearService(), dashboardSettings ?? NewDashboardSettings(),
             schoolHolidays ?? new FakeSchoolHolidays(), new PublicHolidayService(), NewCalendarSettings(),
-            substitutions ?? new FakeSubstitutionEntries(), annualPlanEvents);
+            substitutions ?? new FakeSubstitutionEntries(), timeEntries ?? new FakeTimeEntries(), annualPlanEvents);
+    }
+
+    /// Montag einer Woche, die garantiert in der Zukunft liegt und innerhalb der
+    /// Klausurwochen-Vorausschau — unabhängig davon, welcher Wochentag "heute" gerade ist.
+    private static DateOnly NextIsoWeekMonday()
+    {
+        var reference = DateTime.Today.AddDays(7);
+        return DateOnly.FromDateTime(
+            ISOWeek.ToDateTime(ISOWeek.GetYear(reference), ISOWeek.GetWeekOfYear(reference), DayOfWeek.Monday));
+    }
+
+    [Fact]
+    public void ExamWeekLoads_DreiGeplanteKlausurenInDerselbenWoche_ErzeugtEintrag()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var monday = NextIsoWeekMonday();
+        var exams = new FakeExams([
+            new Exam { GroupId = group.Id, Title = "a", Date = monday, Status = ExamStatus.Planned },
+            new Exam { GroupId = group.Id, Title = "b", Date = monday.AddDays(1), Status = ExamStatus.Planned },
+            new Exam { GroupId = group.Id, Title = "c", Date = monday.AddDays(2), Status = ExamStatus.Planned },
+        ]);
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today }, exams: exams);
+
+        var entry = Assert.Single(vm.ExamWeekLoads);
+        Assert.Equal(3, entry.ExamCount);
+        Assert.True(vm.ExamLoadCard.EffectiveIsVisible);
+    }
+
+    [Fact]
+    public void ExamWeekLoads_WenigeKlausurenProWoche_BleibtLeer()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var monday = NextIsoWeekMonday();
+        var exams = new FakeExams([
+            new Exam { GroupId = group.Id, Title = "a", Date = monday, Status = ExamStatus.Planned },
+            new Exam { GroupId = group.Id, Title = "b", Date = monday.AddDays(1), Status = ExamStatus.Planned },
+        ]);
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today }, exams: exams);
+
+        Assert.Empty(vm.ExamWeekLoads);
+    }
+
+    [Fact]
+    public void ExamWeekLoads_BereitsDurchgefuehrteKlausurenZaehlenNicht()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var monday = NextIsoWeekMonday();
+        var exams = new FakeExams([
+            new Exam { GroupId = group.Id, Title = "a", Date = monday, Status = ExamStatus.Conducted },
+            new Exam { GroupId = group.Id, Title = "b", Date = monday.AddDays(1), Status = ExamStatus.Graded },
+            new Exam { GroupId = group.Id, Title = "c", Date = monday.AddDays(2), Status = ExamStatus.Planned },
+        ]);
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today }, exams: exams);
+
+        Assert.Empty(vm.ExamWeekLoads);
+    }
+
+    [Fact]
+    public void MissingTeachingTime_VergangenerUnterrichtstagOhneErfassung_WirdGemeldet()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var pastDay = today.AddDays(-1);
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = pastDay.DayOfWeek, PeriodNumber = 1 });
+        var periodSchedule = NewPeriodSchedule();
+        periodSchedule.SetPeriods([new PeriodTimeEntry
+            { PeriodNumber = 1, Start = new TimeOnly(8, 0), End = new TimeOnly(8, 45) }]);
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today }, slots: slots, periodSchedule: periodSchedule);
+
+        Assert.Contains(vm.MissingTeachingTimeEntries, i => i.Date == pastDay);
+        Assert.True(vm.MissingTeachingTimeCard.EffectiveIsVisible);
+    }
+
+    [Fact]
+    public void MissingTeachingTime_BereitsErfassterTag_WirdNichtGemeldet()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var pastDay = today.AddDays(-1);
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = pastDay.DayOfWeek, PeriodNumber = 1 });
+        var periodSchedule = NewPeriodSchedule();
+        periodSchedule.SetPeriods([new PeriodTimeEntry
+            { PeriodNumber = 1, Start = new TimeOnly(8, 0), End = new TimeOnly(8, 45) }]);
+        var timeEntries = new FakeTimeEntries();
+        timeEntries.Add(new TimeEntry { Date = pastDay, Category = "Unterricht", DurationMinutes = 45 });
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today },
+            slots: slots, periodSchedule: periodSchedule, timeEntries: timeEntries);
+
+        Assert.DoesNotContain(vm.MissingTeachingTimeEntries, i => i.Date == pastDay);
+    }
+
+    [Fact]
+    public void MissingTeachingTime_KomplettAusgefallenerTag_WirdNichtGemeldet()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var pastDay = today.AddDays(-1);
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = pastDay.DayOfWeek, PeriodNumber = 1 });
+        var periodSchedule = NewPeriodSchedule();
+        periodSchedule.SetPeriods([new PeriodTimeEntry
+            { PeriodNumber = 1, Start = new TimeOnly(8, 0), End = new TimeOnly(8, 45) }]);
+        var substitutions = new FakeSubstitutionEntries();
+        substitutions.Add(new SubstitutionEntry { Date = pastDay, Kind = SubstitutionKind.Cancelled, PeriodNumber = 1 });
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today },
+            slots: slots, periodSchedule: periodSchedule, substitutions: substitutions);
+
+        Assert.DoesNotContain(vm.MissingTeachingTimeEntries, i => i.Date == pastDay);
+    }
+
+    [Fact]
+    public void MissingTeachingTime_SchulferienTagWirdNichtGemeldet()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var pastDay = today.AddDays(-1);
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = pastDay.DayOfWeek, PeriodNumber = 1 });
+        var periodSchedule = NewPeriodSchedule();
+        periodSchedule.SetPeriods([new PeriodTimeEntry
+            { PeriodNumber = 1, Start = new TimeOnly(8, 0), End = new TimeOnly(8, 45) }]);
+        var schoolHolidays = new FakeSchoolHolidays();
+        schoolHolidays.Add(new SchoolHoliday { Name = "Ferien", StartDate = pastDay, EndDate = pastDay });
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today },
+            slots: slots, periodSchedule: periodSchedule, schoolHolidays: schoolHolidays);
+
+        Assert.DoesNotContain(vm.MissingTeachingTimeEntries, i => i.Date == pastDay);
+    }
+
+    [Fact]
+    public void MissingTeachingTime_HeuteVorAblaufDerWartezeit_WirdNichtGemeldet()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = today.DayOfWeek, PeriodNumber = 1 });
+        var periodSchedule = NewPeriodSchedule();
+        // Unterrichtsende liegt garantiert noch keine 30 Minuten zurück.
+        var futureEnd = TimeOnly.FromDateTime(DateTime.Now).AddHours(2);
+        periodSchedule.SetPeriods([new PeriodTimeEntry
+            { PeriodNumber = 1, Start = futureEnd.AddHours(-1), End = futureEnd }]);
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today }, slots: slots, periodSchedule: periodSchedule);
+
+        Assert.DoesNotContain(vm.MissingTeachingTimeEntries, i => i.Date == today);
+    }
+
+    [Fact]
+    public void MissingTeachingTime_HeuteNachAblaufDerWartezeit_WirdGemeldet()
+    {
+        var group = new LearningGroup { Name = "9c" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = today.DayOfWeek, PeriodNumber = 1 });
+        var periodSchedule = NewPeriodSchedule();
+        // Unterrichtsende liegt garantiert mehr als 30 Minuten zurück.
+        var pastEnd = TimeOnly.FromDateTime(DateTime.Now).AddHours(-2);
+        periodSchedule.SetPeriods([new PeriodTimeEntry
+            { PeriodNumber = 1, Start = pastEnd.AddHours(-1), End = pastEnd }]);
+
+        var vm = BuildVm(group, new Lesson { GroupId = group.Id, Date = today }, slots: slots, periodSchedule: periodSchedule);
+
+        Assert.Contains(vm.MissingTeachingTimeEntries, i => i.Date == today);
     }
 
     [Fact]
@@ -226,6 +419,26 @@ public sealed class DashboardViewModelTests
         Assert.Contains(vm.SelectedDayEvents, e => e.Kind == CalendarEventKind.Exam && e.Title == "Test");
     }
 
+    [Fact]
+    public void Kalenderauswahl_SortiertKurseDesTagesVorDenAlphabetischenRest()
+    {
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var selectedDate = today.AddDays(1);
+        var alphabeticallyFirst = new LearningGroup { Name = "10a" };
+        var selectedDayGroup = new LearningGroup { Name = "WAT 10c" };
+        var lessons = new FakeLessons();
+        lessons.Add(new Lesson { GroupId = selectedDayGroup.Id, Date = selectedDate });
+        var vm = BuildVm(alphabeticallyFirst,
+            new Lesson { GroupId = alphabeticallyFirst.Id, Date = today }, lessons: lessons,
+            allGroups: [alphabeticallyFirst, selectedDayGroup]);
+
+        vm.SelectCalendarDayCommand.Execute(vm.CalendarDays.Single(d => d.Date == selectedDate));
+
+        Assert.Equal(selectedDayGroup.Id, vm.CurrentGroups[0].GroupId);
+        Assert.True(vm.CurrentGroups[0].IsOnSelectedDay);
+        Assert.Equal(alphabeticallyFirst.Id, vm.CurrentGroups[1].GroupId);
+    }
+
     [Fact]
     public void Kalender_ZeigtMitarbeitssitzungenAlsEigenenTermintyp()
     {

LehrerApp.Desktop.Tests/DocumentationDialogViewModelTests.cs

@@ -247,6 +247,25 @@ public sealed class DocumentationDialogViewModelTests
         Assert.Equal(groupId, vm.Result.GroupId);
     }
 
+    [Fact]
+    public void GesamteLerngruppe_SaveSpeichertOhneSchuelerbezug()
+    {
+        var groupId = Guid.NewGuid();
+        var wholeGroup = new StudentOption(Guid.Empty, "Gesamte Lerngruppe");
+        var vm = new DocumentationDialogViewModel(Guid.Empty, null, new FakeAttachmentStorage(),
+            [wholeGroup], groupId)
+        {
+            SelectedStudent = wholeGroup, Title = "Klausur planen", TypeName = "Planung / Erinnerung",
+        };
+
+        vm.SaveCommand.Execute(null);
+
+        Assert.NotNull(vm.Result);
+        Assert.Equal(Guid.Empty, vm.Result!.StudentId);
+        Assert.Equal(groupId, vm.Result.GroupId);
+        Assert.Equal(DocumentationType.Planning, vm.Result.Type);
+    }
+
     [Fact]
     public void MitStudentOptions_Bearbeiten_SchuelerIstVorausgewaehlt()
     {

LehrerApp.Desktop.Tests/ExamDialogViewModelTests.cs

@@ -0,0 +1,64 @@
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Desktop.ViewModels.Groups;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class ExamDialogViewModelTests
+{
+    private static ExamDialogViewModel BuildViewModel(List<Exam> existingExams, string dateText,
+        Exam? editingExam = null)
+    {
+        var vm = new ExamDialogViewModel(new FakeExams(existingExams), new FakeCompetencyDomains(),
+            new FakeGradingKeyTemplates(), new GradingService(), Guid.NewGuid(), null, 9,
+            GradingSystem.Grades1To6, "Chemie", isDifferentiated: false, editingExam, null);
+        vm.DateText = dateText;
+        return vm;
+    }
+
+    private static Exam MakeExam(DateOnly date) => new() { GroupId = Guid.NewGuid(), Title = "x", Date = date };
+
+    [Fact]
+    public void WeekLoadHint_WenigeKlausurenInDerWoche_BleibtLeer()
+    {
+        var monday = new DateOnly(2026, 3, 16);
+        var existing = new List<Exam> { MakeExam(monday) };
+
+        var vm = BuildViewModel(existing, monday.AddDays(1).ToString("dd.MM.yyyy"));
+
+        Assert.Equal("", vm.WeekLoadHint);
+    }
+
+    [Fact]
+    public void WeekLoadHint_DritteKlausurInDerWoche_ZeigtHinweis()
+    {
+        var monday = new DateOnly(2026, 3, 16);
+        var existing = new List<Exam> { MakeExam(monday), MakeExam(monday.AddDays(1)) };
+
+        var vm = BuildViewModel(existing, monday.AddDays(2).ToString("dd.MM.yyyy"));
+
+        Assert.Contains("3 Klausuren", vm.WeekLoadHint);
+    }
+
+    [Fact]
+    public void WeekLoadHint_BearbeiteteKlausurZaehltNichtDoppelt()
+    {
+        var monday = new DateOnly(2026, 3, 16);
+        var editing = MakeExam(monday);
+        var existing = new List<Exam> { editing, MakeExam(monday.AddDays(1)) };
+
+        // Nur die eigene Klausur (editing) + eine weitere -> 2 insgesamt, kein Hinweis.
+        var vm = BuildViewModel(existing, monday.ToString("dd.MM.yyyy"), editing);
+
+        Assert.Equal("", vm.WeekLoadHint);
+    }
+
+    [Fact]
+    public void WeekLoadHint_UngueltigesDatum_BleibtLeer()
+    {
+        var vm = BuildViewModel([], "keindatum");
+
+        Assert.Equal("", vm.WeekLoadHint);
+    }
+}

LehrerApp.Desktop.Tests/ExamGradingDialogViewModelTests.cs

@@ -0,0 +1,65 @@
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Desktop.ViewModels.Groups;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+/// Deckt 1.6.3 (Bulk-Aktion "Rest als abwesend markieren") ab — löst das Nutzer-Feedback, dass
+/// Schüler, die nie nachschreiben, sonst dauerhaft eine leere, unberührte Zeile hinterlassen.
+public sealed class ExamGradingDialogViewModelTests
+{
+    [Fact]
+    public void MarkRemainingAbsent_MarktNurUnberührteZeilenAbwesend()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        var studentWithPoints = new Student { FirstName = "Anna", LastName = "Bauer" };
+        var untouchedStudent1 = new Student { FirstName = "Ben", LastName = "Cordes" };
+        var untouchedStudent2 = new Student { FirstName = "Cara", LastName = "Diehl" };
+        var students = new FakeStudents([studentWithPoints, untouchedStudent1, untouchedStudent2]);
+        var memberships = new FakeMemberships(
+        [
+            new GroupMembership { GroupId = group.Id, StudentId = studentWithPoints.Id },
+            new GroupMembership { GroupId = group.Id, StudentId = untouchedStudent1.Id },
+            new GroupMembership { GroupId = group.Id, StudentId = untouchedStudent2.Id },
+        ]);
+        var exam = new Exam
+        {
+            GroupId = group.Id,
+            Title = "Klausur 1",
+            Tasks = [new ExamTask { Nr = 1, MaxPoints = 10 }],
+            GradingKey = GradingService.DefaultKey1To6(),
+        };
+        var results = new FakeResults();
+
+        var vm = new ExamGradingDialogViewModel(results, students, memberships,
+            new GradingService(), exam, group.Id);
+
+        var rowWithPoints = vm.Rows.Single(r => r.StudentId == studentWithPoints.Id);
+        rowWithPoints.Cells[0].TrySetValue(7);
+
+        vm.MarkRemainingAbsentCommand.Execute(null);
+
+        Assert.False(rowWithPoints.Absent);
+        Assert.True(vm.Rows.Single(r => r.StudentId == untouchedStudent1.Id).Absent);
+        Assert.True(vm.Rows.Single(r => r.StudentId == untouchedStudent2.Id).Absent);
+    }
+
+    [Fact]
+    public void MarkRemainingAbsent_LässtBereitsAbwesendMarkierteUnverändert()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        var student = new Student { FirstName = "Ben", LastName = "Cordes" };
+        var students = new FakeStudents([student]);
+        var memberships = new FakeMemberships(
+            [new GroupMembership { GroupId = group.Id, StudentId = student.Id }]);
+        var exam = new Exam { GroupId = group.Id, Title = "Klausur 1", Tasks = [new ExamTask { Nr = 1, MaxPoints = 10 }], GradingKey = GradingService.DefaultKey1To6() };
+        var vm = new ExamGradingDialogViewModel(new FakeResults(), students, memberships,
+            new GradingService(), exam, group.Id);
+
+        vm.Rows[0].Absent = true;
+        vm.MarkRemainingAbsentCommand.Execute(null);
+
+        Assert.True(vm.Rows[0].Absent);
+    }
+}

LehrerApp.Desktop.Tests/ExamsOverviewViewModelTests.cs

@@ -0,0 +1,103 @@
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Desktop.ViewModels.Exams;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+/// Deckt 1.6 (Klausuren-Hauptseite) ab: Priorisierung end-to-end über die ViewModel-Schicht,
+/// Parallelkurs-Umschalter (1.6.4) und Genehmigung/Ankündigung (1.6.5).
+public sealed class ExamsOverviewViewModelTests
+{
+    private static ExamsOverviewViewModel BuildVm(List<LearningGroup> groups, List<Exam> exams,
+        FakeMemberships? memberships = null, FakeResults? results = null) =>
+        new(new FakeExams(exams), results ?? new FakeResults(), new FakeGroups(groups),
+            memberships ?? new FakeMemberships([]), new GradingService(), new SchoolYearService());
+
+    [Fact]
+    public void Load_UnbearbeiteteKorrekturStehtVorGeplanterKlausur()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie", SchoolYear = new SchoolYearService().CurrentSchoolYear() };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var overdue = new Exam { GroupId = group.Id, Title = "Alte Klausur", Status = ExamStatus.Conducted, Date = today.AddDays(-10) };
+        var planned = new Exam { GroupId = group.Id, Title = "Neue Klausur", Status = ExamStatus.Planned, Date = today.AddDays(3) };
+
+        var vm = BuildVm([group], [overdue, planned]);
+        vm.LoadCommand.Execute(null);
+
+        Assert.Equal("Alte Klausur", vm.Rows[0].Title);
+        Assert.Equal("Neue Klausur", vm.Rows[1].Title);
+    }
+
+    [Fact]
+    public void LeereListe_BietetAbsprungZuLerngruppen()
+    {
+        var vm = BuildVm([], []);
+        var navigated = false;
+        vm.OnNavigateToGroups = () => navigated = true;
+
+        vm.LoadCommand.Execute(null);
+        vm.GoToGroupsCommand.Execute(null);
+
+        Assert.True(vm.HasNoExams);
+        Assert.True(navigated);
+    }
+
+    [Fact]
+    public void Load_ParallelkurseWerdenAlsGeschwisterErkannt()
+    {
+        var groupA = new LearningGroup { Name = "Chemie GK Q1", SchoolYear = new SchoolYearService().CurrentSchoolYear() };
+        var groupB = new LearningGroup { Name = "Chemie GK Q1b", SchoolYear = groupA.SchoolYear };
+        var original = new Exam { GroupId = groupA.Id, Title = "Redox", Status = ExamStatus.Planned, Date = DateOnly.FromDateTime(DateTime.Today).AddDays(5) };
+        var duplicate = new Exam
+        {
+            GroupId = groupB.Id, Title = "Redox", Status = ExamStatus.Planned,
+            Date = DateOnly.FromDateTime(DateTime.Today).AddDays(6), SharedExamGroupId = original.Id,
+        };
+
+        var vm = BuildVm([groupA, groupB], [original, duplicate]);
+        vm.LoadCommand.Execute(null);
+
+        vm.SelectedRow = vm.Rows.Single(r => r.Exam.Id == original.Id);
+        Assert.True(vm.SelectedRow.HasSibling);
+        Assert.Single(vm.Siblings);
+        Assert.Equal(duplicate.Id, vm.Siblings[0].Exam.Id);
+    }
+
+    [Fact]
+    public void ToggleApproval_SetztUndLöschtDatum()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie", SchoolYear = new SchoolYearService().CurrentSchoolYear() };
+        var exam = new Exam { GroupId = group.Id, Title = "Klausur", Status = ExamStatus.Planned, Date = DateOnly.FromDateTime(DateTime.Today).AddDays(2) };
+        var vm = BuildVm([group], [exam]);
+        vm.LoadCommand.Execute(null);
+        vm.SelectedRow = vm.Rows[0];
+
+        vm.ToggleApprovalCommand.Execute(null);
+        Assert.NotNull(exam.ApprovalGrantedAt);
+        Assert.StartsWith("Genehmigt am", vm.ApprovalLabel);
+
+        vm.ToggleApprovalCommand.Execute(null);
+        Assert.Null(exam.ApprovalGrantedAt);
+        Assert.Equal("Genehmigung noch ausstehend", vm.ApprovalLabel);
+    }
+
+    [Fact]
+    public void Selection_ZeigtKorrekturfortschrittOderNotenspiegelJeNachStatus()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie", SchoolYear = new SchoolYearService().CurrentSchoolYear() };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var conducted = new Exam { GroupId = group.Id, Title = "Läuft", Status = ExamStatus.Conducted, Date = today.AddDays(-2) };
+        var returned = new Exam { GroupId = group.Id, Title = "Fertig", Status = ExamStatus.Returned, Date = today.AddDays(-20) };
+        var vm = BuildVm([group], [conducted, returned]);
+        vm.LoadCommand.Execute(null);
+
+        vm.SelectedRow = vm.Rows.Single(r => r.Exam.Id == conducted.Id);
+        Assert.True(vm.ShowCorrectionProgress);
+        Assert.False(vm.ShowGradeSummary);
+
+        vm.SelectedRow = vm.Rows.Single(r => r.Exam.Id == returned.Id);
+        Assert.False(vm.ShowCorrectionProgress);
+        Assert.True(vm.ShowGradeSummary);
+    }
+}

LehrerApp.Desktop.Tests/Fakes.cs

@@ -170,6 +170,7 @@ public class FakeSessions(List<ParticipationSession> all) : IParticipationSessio
 {
     public List<ParticipationSession> GetByGroup(Guid groupId) => all.Where(s => s.GroupId == groupId).ToList();
     public ParticipationSession? GetById(Guid id) => all.FirstOrDefault(s => s.Id == id);
+    public List<ParticipationSession> GetAll() => all.ToList();
     public void Save(ParticipationSession session)
     {
         all.RemoveAll(s => s.Id == session.Id);
@@ -474,6 +475,56 @@ public class FakeAnnualPlanEvents : IAnnualPlanEventRepository
     public void Delete(Guid id) => _all.RemoveAll(e => e.Id == id);
 }
 
+public class FakeUntisAbsenceCache : IUntisAbsenceCacheRepository
+{
+    private readonly List<UntisAbsenceCacheEntry> _all = [];
+    public List<UntisAbsenceCacheEntry> GetByClassAndRange(string className, int startDate, int endDate) =>
+        _all.Where(e => e.ClassName == className && e.Date >= startDate && e.Date <= endDate).ToList();
+    public void ReplaceRange(string className, int startDate, int endDate, IEnumerable<UntisAbsenceCacheEntry> entries)
+    {
+        _all.RemoveAll(e => e.ClassName == className && e.Date >= startDate && e.Date <= endDate);
+        _all.AddRange(entries);
+    }
+    public void InsertRange(IEnumerable<UntisAbsenceCacheEntry> entries) => _all.AddRange(entries);
+}
+
+public class FakeUntisClassRegisterCache : IUntisClassRegisterCacheRepository
+{
+    private readonly List<UntisClassRegisterCacheEntry> _all = [];
+    public List<UntisClassRegisterCacheEntry> GetByClassAndRange(string className, int startDate, int endDate) =>
+        _all.Where(e => e.ClassName == className && e.Date >= startDate && e.Date <= endDate).ToList();
+    public void ReplaceRange(string className, int startDate, int endDate, IEnumerable<UntisClassRegisterCacheEntry> entries)
+    {
+        _all.RemoveAll(e => e.ClassName == className && e.Date >= startDate && e.Date <= endDate);
+        _all.AddRange(entries);
+    }
+    public void InsertRange(IEnumerable<UntisClassRegisterCacheEntry> entries) => _all.AddRange(entries);
+}
+
+public class FakeUntisStudentRosterCache : IUntisStudentRosterCacheRepository
+{
+    private readonly List<UntisStudentRosterCacheEntry> _all = [];
+    public List<UntisStudentRosterCacheEntry> GetByClass(string className) =>
+        _all.Where(e => e.ClassName == className).ToList();
+    public void ReplaceAll(string className, IEnumerable<UntisStudentRosterCacheEntry> entries)
+    {
+        _all.RemoveAll(e => e.ClassName == className);
+        _all.AddRange(entries);
+    }
+}
+
+public class FakeUntisCacheFetchStates : IUntisCacheFetchStateRepository
+{
+    private readonly List<UntisCacheFetchState> _all = [];
+    public UntisCacheFetchState? Get(string className, UntisCacheKind kind) =>
+        _all.FirstOrDefault(s => s.ClassName == className && s.Kind == kind);
+    public void Save(UntisCacheFetchState state)
+    {
+        _all.RemoveAll(s => s.ClassName == state.ClassName && s.Kind == state.Kind);
+        _all.Add(state);
+    }
+}
+
 public class FakeWorkTasks : IWorkTaskRepository
 {
     private readonly List<WorkTask> _all = [];

LehrerApp.Desktop.Tests/FractionWidthConverterTests.cs

@@ -0,0 +1,37 @@
+using System.Globalization;
+using LehrerApp.Desktop.Converters;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class FractionWidthConverterTests
+{
+    [Fact]
+    public void Convert_MultipliziertTrackbreiteMitAnteil()
+    {
+        var result = FractionWidthConverter.Instance.Convert(
+            [200d, 0.25d], typeof(double), null, CultureInfo.InvariantCulture);
+
+        Assert.Equal(50d, result);
+    }
+
+    [Fact]
+    public void Convert_LiefertNullBreiteBeiUngueltigenWerten()
+    {
+        // Bounds.Width kann vor dem ersten Layout-Pass NaN sein (Element noch nicht gemessen) —
+        // darf nicht zu einer negativen oder undefinierten Breite führen.
+        Assert.Equal(0d, FractionWidthConverter.Instance.Convert(
+            [double.NaN, 0.5d], typeof(double), null, CultureInfo.InvariantCulture));
+        Assert.Equal(0d, FractionWidthConverter.Instance.Convert(
+            ["not a double", 0.5d], typeof(double), null, CultureInfo.InvariantCulture));
+    }
+
+    [Fact]
+    public void Convert_ClamptNegativeErgebnisseAufNull()
+    {
+        var result = FractionWidthConverter.Instance.Convert(
+            [100d, -0.2d], typeof(double), null, CultureInfo.InvariantCulture);
+
+        Assert.Equal(0d, result);
+    }
+}

LehrerApp.Desktop.Tests/GlobalSearchViewModelTests.cs

@@ -0,0 +1,103 @@
+using LehrerApp.Core.Models;
+using LehrerApp.Desktop.ViewModels;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class GlobalSearchViewModelTests
+{
+    [Fact]
+    public void LeereSuche_ZeigtSchnellaktionen()
+    {
+        var vm = BuildVm();
+
+        Assert.Collection(vm.Results,
+            item => Assert.Equal(GlobalSearchAction.NewTask, item.Action),
+            item => Assert.Equal(GlobalSearchAction.NewReminder, item.Action),
+            item => Assert.Equal(GlobalSearchAction.NewStudent, item.Action),
+            item => Assert.Equal(GlobalSearchAction.NewGroupDocumentation, item.Action));
+        Assert.Same(vm.Results[0], vm.SelectedResult);
+    }
+
+    [Fact]
+    public void Suche_FindetSchuelerGruppeKlausurUndAufgabe()
+    {
+        var group = new LearningGroup { Name = "9 Chemie", SchoolYear = "2026/27", GradeLevel = 9 };
+        var student = new Student { FirstName = "Mia", LastName = "Chemie" };
+        var exam = new Exam { GroupId = group.Id, Title = "Chemie-Test", Date = new DateOnly(2026, 9, 1) };
+        var tasks = new FakeWorkTasks();
+        tasks.Add(new WorkTask { GroupId = group.Id, Title = "Chemie-Klausur korrigieren" });
+        var vm = BuildVm([student], [group], [exam], tasks);
+
+        vm.Query = "Chemie";
+
+        Assert.Contains(vm.Results, x => x.Kind == GlobalSearchResultKind.Student && x.EntityId == student.Id);
+        Assert.Contains(vm.Results, x => x.Kind == GlobalSearchResultKind.Group && x.EntityId == group.Id);
+        Assert.Contains(vm.Results, x => x.Kind == GlobalSearchResultKind.Exam && x.EntityId == exam.Id);
+        Assert.Contains(vm.Results, x => x.Kind == GlobalSearchResultKind.Task && x.Title.Contains("korrigieren"));
+    }
+
+    [Fact]
+    public async Task TrefferAusfuehren_NavigiertUndSchliesstPalette()
+    {
+        var student = new Student { FirstName = "Mia", LastName = "Muster" };
+        var vm = BuildVm([student]);
+        vm.Query = "Muster";
+        var result = Assert.Single(vm.Results, x => x.Kind == GlobalSearchResultKind.Student);
+        GlobalSearchResult? navigated = null;
+        var closed = false;
+        vm.OnNavigate = x => navigated = x;
+        vm.OnClose = () => closed = true;
+
+        await vm.ExecuteCommand.ExecuteAsync(result);
+
+        Assert.Same(result, navigated);
+        Assert.True(closed);
+    }
+
+    [Fact]
+    public async Task ErinnerungSchnellErfassen_StartetDialogAlsErinnerung()
+    {
+        var vm = BuildVm();
+        bool? reminder = null;
+        vm.OnQuickAddTask = value => { reminder = value; return Task.CompletedTask; };
+        var action = vm.Results.Single(x => x.Action == GlobalSearchAction.NewReminder);
+
+        await vm.ExecuteCommand.ExecuteAsync(action);
+
+        Assert.True(reminder);
+    }
+
+    [Fact]
+    public void Suche_FindetAktiveGruppeUeberFachUndZeigtFachImUntertitel()
+    {
+        var subject = new Subject { Name = "Wirtschaft-Arbeit-Technik", ShortName = "WAT" };
+        var group = new LearningGroup { Name = "10c", SubjectId = subject.Id, SchoolYear = "2026/27", GradeLevel = 10 };
+        var vm = BuildVm(groups: [group], subjects: [subject]);
+
+        vm.Query = "wat";
+
+        var result = Assert.Single(vm.Results, x => x.Kind == GlobalSearchResultKind.Group);
+        Assert.Contains("WAT", result.Subtitle);
+    }
+
+    [Fact]
+    public void Suche_UeberspringtArchivierteSchuelerUndGruppenSamtDerenKlausuren()
+    {
+        var archivedGroup = new LearningGroup { Name = "Testkurs Vorjahr", IsActive = false };
+        var archivedStudent = new Student { FirstName = "Test", LastName = "Archiv", IsActive = false };
+        var exam = new Exam { GroupId = archivedGroup.Id, Title = "Testklausur" };
+        var vm = BuildVm([archivedStudent], [archivedGroup], [exam]);
+
+        vm.Query = "Test";
+
+        Assert.DoesNotContain(vm.Results, x => x.Kind is GlobalSearchResultKind.Student
+            or GlobalSearchResultKind.Group or GlobalSearchResultKind.Exam);
+    }
+
+    private static GlobalSearchViewModel BuildVm(List<Student>? students = null,
+        List<LearningGroup>? groups = null, List<Exam>? exams = null, FakeWorkTasks? tasks = null,
+        List<Subject>? subjects = null) =>
+        new(new FakeStudents(students ?? []), new FakeGroups(groups ?? []),
+            new FakeSubjects(subjects ?? []), new FakeExams(exams ?? []), tasks ?? new FakeWorkTasks());
+}

LehrerApp.Desktop.Tests/GroupDetailViewModelTests.cs

@@ -18,8 +18,8 @@ public sealed class GroupDetailViewModelTests
         var grades = new FakeGrades();
 
         var vm = new GroupDetailViewModel(groups, students, memberships, subjects, exams, grades, tasks,
-            new GroupOverviewViewModel(new FakeLessons(), exams, new FakeSessions([]), new FakeEntries(), students,
+            new GroupOverviewViewModel(new FakeLessons(), exams, new FakeResults(), new FakeSessions([]), new FakeEntries(), students,
-                new FakeDocumentation(), tasks, new AttendanceBalanceService(), new SchoolYearService()),
+                new FakeDocumentation(), tasks, groups, new AttendanceBalanceService(), new GradingService(), new SchoolYearService()),
             new ParticipationTabViewModel(new FakeSessions([]), new FakeEntries(), new FakeAspects(),
                 students, memberships, groups, new FakeCompetencyDomains()),
             new GradeOverviewTabViewModel(grades, exams, new FakeResults(), students, memberships, new GradingService()),

LehrerApp.Desktop.Tests/GroupDocumentationQuickViewModelTests.cs

@@ -0,0 +1,26 @@
+using LehrerApp.Core.Models;
+using LehrerApp.Desktop.ViewModels.Students;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class GroupDocumentationQuickViewModelTests
+{
+    [Fact]
+    public void Save_ErstelltPlanungFuerGesamteLerngruppe()
+    {
+        var group = new GroupDocumentationOption(Guid.NewGuid(), "10c · WAT");
+        var vm = new GroupDocumentationQuickViewModel([group])
+        {
+            SelectedGroup = group, Title = "Klausur ankündigen", Content = "Termin abstimmen",
+        };
+
+        vm.SaveCommand.Execute(null);
+
+        Assert.NotNull(vm.Result);
+        Assert.Equal(Guid.Empty, vm.Result!.StudentId);
+        Assert.Equal(group.Id, vm.Result.GroupId);
+        Assert.Equal(DocumentationType.Planning, vm.Result.Type);
+        Assert.True(vm.Result.ExcludeFromWebUntisSync);
+    }
+}

LehrerApp.Desktop.Tests/GroupDocumentationTabViewModelTests.cs

@@ -36,6 +36,25 @@ public sealed class GroupDocumentationTabViewModelTests
         Assert.Equal("Alt", vm.Entries[1].Model.Title);
     }
 
+    [Fact]
+    public void Initialize_ZeigtGruppenweitenEintragAuchOhneSchueler()
+    {
+        var group = new LearningGroup { Name = "10c" };
+        var docs = new FakeDocumentation();
+        docs.Add(new Documentation
+        {
+            StudentId = Guid.Empty, GroupId = group.Id, Type = DocumentationType.Planning,
+            Title = "Klausur planen", Date = new DateOnly(2026, 9, 1),
+        });
+
+        var vm = BuildVm([], [group], docs);
+        vm.Initialize(group.Id);
+
+        var entry = Assert.Single(vm.Entries);
+        Assert.Equal("Gesamte Lerngruppe", entry.StudentName);
+        Assert.Equal("Planung / Erinnerung", entry.TypeLabel);
+    }
+
     [Fact]
     public void Initialize_EintragAusAndererGruppe_WirdMitangezeigtAberAlsFremdMarkiert()
     {

LehrerApp.Desktop.Tests/GroupListViewModelTests.cs

@@ -5,76 +5,69 @@ using Xunit;
 
 namespace LehrerApp.Desktop.Tests;
 
-/// Tests für den Schnellüberblick im Auswahl-Panel der Gruppenliste (Nutzer-Feedback:
+/// <summary>Tests für die direkte, einlagige Lerngruppen-Navigation.</summary>
-/// "oberhalb der Buttonliste ein paar Daten auswerfen. Nächste Stunde, nächste Arbeit,
-/// wichtige Todos").
 public sealed class GroupListViewModelTests
 {
-    private static GroupListViewModel BuildVm(LearningGroup group, FakeLessons? lessons = null,
+    private static GroupListViewModel BuildVm(params LearningGroup[] groups) =>
-        FakeExams? exams = null, FakeWorkTasks? tasks = null) =>
+        new(new FakeGroups([.. groups]), new FakeSubjects([]), new SchoolYearService());
-        new(new FakeGroups([group]), new FakeSubjects([]), new SchoolYearService(),
-            lessons ?? new FakeLessons(), exams ?? new FakeExams([]), tasks ?? new FakeWorkTasks());
 
     [Fact]
-    public void SelectedGroup_OhneDatenZeigtKeinenSchnellueberblick()
+    public void Gruppenkarte_OeffnetDirektDieUebersicht()
     {
-        var group = new LearningGroup { Name = "9c" };
+        var group = CurrentGroup("9c");
         var vm = BuildVm(group);
+        Guid? openedId = null;
+        int? openedTab = null;
+        vm.OnNavigateToDetail = (id, tab) => { openedId = id; openedTab = tab; };
 
-        vm.SelectedGroup = vm.Groups.Count > 0 ? vm.Groups[0] : new GroupListItem(group, "");
+        Assert.Single(vm.Groups).OpenCommand.Execute(null);
 
-        Assert.False(vm.QuickHasAnything);
+        Assert.Equal(group.Id, openedId);
+        Assert.Equal(0, openedTab);
     }
 
     [Fact]
-    public void SelectedGroup_ZeigtNaechsteGeplanteStundeUndKlausur()
+    public async Task Verwaltungsmenue_BearbeitetDieGewaehlteKarteOhneZwischenauswahl()
     {
-        var group = new LearningGroup { Name = "9c" };
+        var first = CurrentGroup("9a");
-        var today = DateOnly.FromDateTime(DateTime.Today);
+        var second = CurrentGroup("9b");
-        var lessons = new FakeLessons();
+        var vm = BuildVm(first, second);
-        lessons.Add(new Lesson { GroupId = group.Id, Date = today.AddDays(3), Topic = "Redox", Status = LessonStatus.Planned });
+        Guid? editedId = null;
-        var exams = new FakeExams([new Exam { GroupId = group.Id, Date = today.AddDays(10), Title = "Klausur 1" }]);
+        vm.OnEditGroup = id => { editedId = id; return Task.CompletedTask; };
-        var vm = BuildVm(group, lessons: lessons, exams: exams);
+        var secondItem = vm.Groups.Single(x => x.Id == second.Id);
 
-        vm.SelectedGroup = new GroupListItem(group, "");
+        await secondItem.EditCommand.ExecuteAsync(null);
 
-        Assert.True(vm.QuickHasNextLesson);
+        Assert.Equal(second.Id, editedId);
-        Assert.Contains("Redox", vm.QuickNextLessonLabel);
-        Assert.True(vm.QuickHasNextExam);
-        Assert.Contains("Klausur 1", vm.QuickNextExamLabel);
-        Assert.True(vm.QuickHasAnything);
     }
 
     [Fact]
-    public void SelectedGroup_ZeigtOffeneAufgabenDieserGruppeSortiertNachFaelligkeit()
+    public void Suche_FiltertWeiterhinNachGruppenname()
     {
-        var group = new LearningGroup { Name = "9c" };
+        var vm = BuildVm(CurrentGroup("9 Chemie"), CurrentGroup("10 Mathematik"));
-        var today = DateOnly.FromDateTime(DateTime.Today);
-        var tasks = new FakeWorkTasks();
-        tasks.Add(new WorkTask { GroupId = group.Id, Title = "Bald fällig", DueDate = today.AddDays(1), Status = WorkTaskStatus.Open });
-        tasks.Add(new WorkTask { GroupId = group.Id, Title = "Erledigt", DueDate = today, Status = WorkTaskStatus.Done });
-        tasks.Add(new WorkTask { GroupId = Guid.NewGuid(), Title = "Andere Gruppe", DueDate = today, Status = WorkTaskStatus.Open });
-        var vm = BuildVm(group, tasks: tasks);
 
-        vm.SelectedGroup = new GroupListItem(group, "");
+        vm.SearchText = "Chemie";
 
-        Assert.True(vm.QuickHasTasks);
+        Assert.Equal("9 Chemie", Assert.Single(vm.Groups).Name);
-        Assert.Equal("Bald fällig", Assert.Single(vm.QuickTasks).Title);
     }
 
     [Fact]
-    public void SelectedGroup_Zuruecksetzen_LeertSchnellueberblick()
+    public void Archivieren_WirktAufDieKarteUndEntferntSieAusDerAktivenListe()
     {
-        var group = new LearningGroup { Name = "9c" };
+        var group = CurrentGroup("9c");
-        var today = DateOnly.FromDateTime(DateTime.Today);
+        var vm = BuildVm(group);
-        var exams = new FakeExams([new Exam { GroupId = group.Id, Date = today.AddDays(10), Title = "Klausur 1" }]);
+        var item = Assert.Single(vm.Groups);
-        var vm = BuildVm(group, exams: exams);
-        vm.SelectedGroup = new GroupListItem(group, "");
-        Assert.True(vm.QuickHasAnything);
 
-        vm.SelectedGroup = null;
+        item.ToggleArchiveCommand.Execute(null);
 
-        Assert.False(vm.QuickHasAnything);
+        Assert.False(group.IsActive);
-        Assert.Empty(vm.QuickTasks);
+        Assert.Empty(vm.Groups);
     }
+
+    private static LearningGroup CurrentGroup(string name) => new()
+    {
+        Name = name,
+        SchoolYear = new SchoolYearService().CurrentSchoolYear(),
+        IsActive = true,
+    };
 }

LehrerApp.Desktop.Tests/GroupOverviewViewModelTests.cs

@@ -12,10 +12,13 @@ public sealed class GroupOverviewViewModelTests
 {
     private static GroupOverviewViewModel NewVm(FakeLessons? lessons = null, FakeExams? exams = null,
         FakeSessions? sessions = null, FakeEntries? entries = null, FakeStudents? students = null,
-        FakeDocumentation? documentation = null, FakeWorkTasks? tasks = null) =>
+        FakeDocumentation? documentation = null, FakeWorkTasks? tasks = null,
-        new(lessons ?? new FakeLessons(), exams ?? new FakeExams([]), sessions ?? new FakeSessions([]),
+        FakeResults? results = null, FakeGroups? groups = null) =>
+        new(lessons ?? new FakeLessons(), exams ?? new FakeExams([]), results ?? new FakeResults(),
+            sessions ?? new FakeSessions([]),
             entries ?? new FakeEntries(), students ?? new FakeStudents([]), documentation ?? new FakeDocumentation(),
-            tasks ?? new FakeWorkTasks(), new AttendanceBalanceService(), new SchoolYearService());
+            tasks ?? new FakeWorkTasks(), groups ?? new FakeGroups([]), new AttendanceBalanceService(),
+            new GradingService(), new SchoolYearService());
 
     private static (GroupOverviewViewModel Vm, FakeLessons Lessons, FakeExams Exams,
         FakeSessions Sessions, FakeEntries Entries, FakeStudents Students, Guid GroupId) BuildScenario(
@@ -76,6 +79,86 @@ public sealed class GroupOverviewViewModelTests
         Assert.Contains("Klassenarbeit 2", vm.NextExamLabel);
     }
 
+    [Fact]
+    public void Vorjahresvergleich_OhneVerknuepfteVorgaengergruppe_BleibtVerborgen()
+    {
+        var groupId = Guid.NewGuid();
+        var groups = new FakeGroups([new LearningGroup { Id = groupId, GradingSystem = GradingSystem.Grades1To6 }]);
+        var vm = NewVm(groups: groups);
+
+        vm.Initialize(groupId, "Testkurs");
+
+        Assert.False(vm.HasYearComparison);
+    }
+
+    [Fact]
+    public void Vorjahresvergleich_VorgaengerOhneKlausurergebnisse_BleibtVerborgen()
+    {
+        var previousId = Guid.NewGuid();
+        var groupId = Guid.NewGuid();
+        var groups = new FakeGroups([
+            new LearningGroup { Id = groupId, GradingSystem = GradingSystem.Grades1To6, PreviousGroupId = previousId },
+            new LearningGroup { Id = previousId, GradingSystem = GradingSystem.Grades1To6 },
+        ]);
+        var vm = NewVm(groups: groups);
+
+        vm.Initialize(groupId, "Testkurs");
+
+        Assert.False(vm.HasYearComparison);
+    }
+
+    [Fact]
+    public void Vorjahresvergleich_ZeigtDurchschnitteBeiderJahreAn()
+    {
+        var previousId = Guid.NewGuid();
+        var groupId = Guid.NewGuid();
+        var groups = new FakeGroups([
+            new LearningGroup { Id = groupId, GradingSystem = GradingSystem.Grades1To6, PreviousGroupId = previousId },
+            new LearningGroup { Id = previousId, GradingSystem = GradingSystem.Grades1To6 },
+        ]);
+
+        var previousExam = new Exam { Id = Guid.NewGuid(), GroupId = previousId };
+        var currentExam = new Exam { Id = Guid.NewGuid(), GroupId = groupId };
+        var exams = new FakeExams([previousExam, currentExam]);
+
+        var results = new FakeResults();
+        results.Add(new ExamResult { ExamId = previousExam.Id, StudentId = Guid.NewGuid(), Grade = "2" });
+        results.Add(new ExamResult { ExamId = previousExam.Id, StudentId = Guid.NewGuid(), Grade = "4" });
+        results.Add(new ExamResult { ExamId = currentExam.Id, StudentId = Guid.NewGuid(), Grade = "1" });
+        // Abwesende und leere Ergebnisse fließen bewusst nicht in den Schnitt ein.
+        results.Add(new ExamResult { ExamId = currentExam.Id, StudentId = Guid.NewGuid(), Absent = true, Grade = "6" });
+
+        var vm = NewVm(exams: exams, results: results, groups: groups);
+
+        vm.Initialize(groupId, "Testkurs");
+
+        Assert.True(vm.HasYearComparison);
+        Assert.Contains("Dieses Jahr: Ø 1,0 (1 Klausuren)", vm.YearComparisonLabel);
+        Assert.Contains("Vorjahr: Ø 3,0 (2 Klausuren)", vm.YearComparisonLabel);
+    }
+
+    [Fact]
+    public void Vorjahresvergleich_OhneEigeneKlausurenZeigtNurVorjahr()
+    {
+        var previousId = Guid.NewGuid();
+        var groupId = Guid.NewGuid();
+        var groups = new FakeGroups([
+            new LearningGroup { Id = groupId, GradingSystem = GradingSystem.Grades1To6, PreviousGroupId = previousId },
+            new LearningGroup { Id = previousId, GradingSystem = GradingSystem.Grades1To6 },
+        ]);
+        var previousExam = new Exam { Id = Guid.NewGuid(), GroupId = previousId };
+        var exams = new FakeExams([previousExam]);
+        var results = new FakeResults();
+        results.Add(new ExamResult { ExamId = previousExam.Id, StudentId = Guid.NewGuid(), Grade = "3" });
+
+        var vm = NewVm(exams: exams, results: results, groups: groups);
+
+        vm.Initialize(groupId, "Testkurs");
+
+        Assert.True(vm.HasYearComparison);
+        Assert.Contains("noch keine Klausur", vm.YearComparisonLabel);
+    }
+
     [Fact]
     public void Mitarbeit_OhneSitzungenZeigtHinweisOhneWarnung()
     {

LehrerApp.Desktop.Tests/LessonSchedulingServiceTests.cs

@@ -0,0 +1,90 @@
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Desktop.ViewModels.Planning;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class LessonSchedulingServiceTests
+{
+    [Fact]
+    public void UnitPicker_SchlaegtLaufendeEinheitVor_UndSpeichertNeuanlageNochNicht()
+    {
+        var groupId = Guid.NewGuid();
+        var planned = new Unit { GroupId = groupId, Title = "Später", Status = UnitStatus.Planned };
+        var active = new Unit { GroupId = groupId, Title = "Aktuell", Status = UnitStatus.Active };
+        var repo = new FakeUnits();
+        repo.Add(planned); repo.Add(active);
+        var vm = new TimetableUnitPickerViewModel(repo, groupId, "10c", new(2026, 9, 2), 3);
+
+        Assert.Equal(active.Id, vm.SelectedUnit?.Model.Id);
+        vm.NewUnitTitle = "Neue Reihe";
+        vm.SaveCommand.Execute(null);
+
+        Assert.True(vm.ResultIsNew);
+        Assert.Equal("Neue Reihe", vm.Result?.Title);
+        Assert.Null(repo.GetById(vm.Result!.Id));
+    }
+
+    [Fact]
+    public void Move_AendertDatumUndStunde_UndRuecktNurNichtDurchgefuehrteFolgestundenNach()
+    {
+        var unitId = Guid.NewGuid();
+        var groupId = Guid.NewGuid();
+        var moved = new Lesson { UnitId = unitId, GroupId = groupId, Date = new(2026, 9, 1), LessonNumber = 2 };
+        var draftFollowing = new Lesson { UnitId = unitId, GroupId = groupId, Date = new(2026, 9, 3), Status = LessonStatus.Draft };
+        var conducted = new Lesson { UnitId = unitId, GroupId = groupId, Date = new(2026, 9, 4), Status = LessonStatus.Conducted };
+        var repo = new FakeLessons();
+        repo.Add(moved); repo.Add(draftFollowing); repo.Add(conducted);
+
+        new LessonSchedulingService(repo).Move(moved, new(2026, 9, 8), 5, shiftFollowing: true);
+
+        Assert.Equal(new DateOnly(2026, 9, 8), moved.Date);
+        Assert.Equal(5, moved.LessonNumber);
+        Assert.Equal(new DateOnly(2026, 9, 10), draftFollowing.Date);
+        Assert.Equal(new DateOnly(2026, 9, 4), conducted.Date);
+    }
+
+    [Fact]
+    public void SplitAndMoveSecondPart_TeiltAuchEineUeberDieGrenzeLaufendePhase()
+    {
+        var source = new Lesson
+        {
+            UnitId = Guid.NewGuid(), GroupId = Guid.NewGuid(), Date = new(2026, 9, 1),
+            LessonNumber = 3, Topic = "Fotosynthese", Homework = "Aufgabe 2",
+            Phases =
+            [
+                new LessonPhaseStep { Name = "Einstieg", DurationMinutes = 30 },
+                new LessonPhaseStep { Name = "Experiment", DurationMinutes = 30 },
+                new LessonPhaseStep { Name = "Sicherung", DurationMinutes = 20 },
+            ],
+        };
+        var repo = new FakeLessons();
+        repo.Add(source);
+
+        var continuation = new LessonSchedulingService(repo).SplitAndMoveSecondPart(source, 45,
+            new(2026, 9, 3), 6, new TimeOnly(12, 15));
+
+        Assert.Equal([30, 15], source.Phases.Select(p => p.DurationMinutes));
+        Assert.Equal([15, 20], continuation.Phases.Select(p => p.DurationMinutes));
+        Assert.Equal("Fotosynthese – Fortsetzung", continuation.Topic);
+        Assert.Null(source.Homework);
+        Assert.Equal("Aufgabe 2", continuation.Homework);
+        Assert.Equal(6, continuation.LessonNumber);
+    }
+
+    [Fact]
+    public void Move_LehntBelegtenZielterminAb()
+    {
+        var groupId = Guid.NewGuid();
+        var source = new Lesson { GroupId = groupId, Date = new(2026, 9, 1), LessonNumber = 1 };
+        var occupied = new Lesson { GroupId = groupId, Date = new(2026, 9, 2), LessonNumber = 4 };
+        var repo = new FakeLessons();
+        repo.Add(source); repo.Add(occupied);
+
+        var error = Assert.Throws<InvalidOperationException>(() =>
+            new LessonSchedulingService(repo).Move(source, occupied.Date, 4, false));
+
+        Assert.Contains("bereits eine Planung", error.Message);
+    }
+}

LehrerApp.Desktop.Tests/QuickInputViewModelTests.cs

@@ -83,6 +83,67 @@ public sealed class QuickInputViewModelTests
         Assert.Equal(0.4, vm.CurrentStudentContentOpacity);
     }
 
+    [Fact]
+    public void ClearRating_SetztVersehentlichGesetzteBewertungAufNichtBewertetZurueck()
+    {
+        var aspects = new List<AspectColumnDef>
+        {
+            new(new ParticipationAspect { Key = "quality", Label = "Qualität" }),
+        };
+        var rows = new List<ParticipationStudentRow>
+        {
+            new(Guid.NewGuid(), "Anna", new ParticipationEntry(), aspects, []),
+        };
+        var vm = new QuickInputViewModel(rows, aspects);
+        vm.SetRatingByNumber(4); // aus Versehen eine Note für Qualität vergeben
+
+        vm.ClearRating();
+
+        Assert.Null(vm.AspectRows[0].Value);
+        Assert.Null(rows[0].GetRating("quality"));
+    }
+
+    [Fact]
+    public void SetDayHighlight_SpeichertAufDerZeileUndAktualisiertDieAnzeige()
+    {
+        var aspects = new List<AspectColumnDef>
+        {
+            new(new ParticipationAspect { Key = "quality", Label = "Qualität" }),
+        };
+        var rows = new List<ParticipationStudentRow>
+        {
+            new(Guid.NewGuid(), "Anna", new ParticipationEntry(), aspects, []),
+        };
+        var vm = new QuickInputViewModel(rows, aspects);
+
+        vm.SetDayHighlight(DayHighlightKind.Standout);
+
+        Assert.Equal(DayHighlightKind.Standout, rows[0].DayHighlight);
+        Assert.Equal("👑", vm.CurrentStudentDayHighlightSymbol);
+        Assert.Equal("Spitzentag", vm.CurrentStudentDayHighlightLabel);
+    }
+
+    [Fact]
+    public void ZurueckZuVorherigemSchueler_ZeigtDessenTagesflaggeWiederAn()
+    {
+        var aspects = new List<AspectColumnDef>
+        {
+            new(new ParticipationAspect { Key = "quality", Label = "Qualität" }),
+        };
+        var rows = new List<ParticipationStudentRow>
+        {
+            new(Guid.NewGuid(), "Anna", new ParticipationEntry(), aspects, []),
+            new(Guid.NewGuid(), "Ben", new ParticipationEntry(), aspects, []),
+        };
+        var vm = new QuickInputViewModel(rows, aspects);
+
+        vm.SetDayHighlight(DayHighlightKind.Sleepy); // Anna
+        vm.NextStudent();                            // zu Ben, keine Flagge
+        vm.PreviousStudent();                        // zurück zu Anna
+
+        Assert.Equal(DayHighlightKind.Sleepy, vm.CurrentStudentDayHighlight);
+    }
+
     [Fact]
     public void VorherigerAspekt_SpringtRueckwaertsMitUmlauf()
     {

LehrerApp.Desktop.Tests/SchoolDayWeatherSummaryTests.cs

@@ -0,0 +1,139 @@
+using LehrerApp.Core.Models;
+using LehrerApp.Desktop.ViewModels.Planning;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class SchoolDayWeatherSummaryTests
+{
+    private static readonly DateOnly Day = new(2026, 8, 24);
+
+    [Fact]
+    public void From_GewitterHatVorrangVorSturmUndRegen()
+    {
+        var snapshot = Snapshot(
+            Hour(8, code: 61, rain: 2, gust: 70),
+            Hour(10, code: 95, rain: 1, gust: 80));
+
+        var summary = SchoolDayWeatherSummary.From(snapshot, Day);
+
+        Assert.Equal(SchoolDayWeatherKind.Thunderstorm, summary!.Kind);
+        Assert.Equal("⛈️", summary.Symbol);
+    }
+
+    [Fact]
+    public void From_BoeAbBeaufortAcht_WirdAlsSturmAngezeigt()
+    {
+        var summary = SchoolDayWeatherSummary.From(Snapshot(Hour(10, gust: 62)), Day);
+
+        Assert.Equal(SchoolDayWeatherKind.Storm, summary!.Kind);
+        Assert.Equal("💨", summary.Symbol);
+    }
+
+    [Fact]
+    public void From_NaechtlicheBoeBeeinflusstSchultagNicht()
+    {
+        var snapshot = Snapshot(Hour(10, cloud: 10), Hour(23, gust: 90));
+
+        var summary = SchoolDayWeatherSummary.From(snapshot, Day);
+
+        Assert.Equal(20, summary!.MaxWindGustKmh);
+        Assert.Equal(SchoolDayWeatherKind.Sunny, summary!.Kind);
+    }
+
+    [Fact]
+    public void From_VerwendetFuerKennzahlenNurAchtBisSechzehnUhr()
+    {
+        var snapshot = Snapshot(
+            Hour(7, temperature: 5, rain: 3, probability: 95, sunshineMinutes: 0),
+            Hour(8, temperature: 12, probability: 20, sunshineMinutes: 30),
+            Hour(16, temperature: 17, probability: 65, sunshineMinutes: 45),
+            Hour(17, temperature: 25, rain: 4, probability: 99, sunshineMinutes: 60));
+
+        var summary = SchoolDayWeatherSummary.From(snapshot, Day);
+
+        Assert.Equal(12, summary!.MinTemperatureC);
+        Assert.Equal(17, summary.MaxTemperatureC);
+        Assert.Equal(0, summary.PrecipitationMm);
+        Assert.Equal(65, summary.MaxHourlyPrecipitationProbabilityPercent);
+        Assert.Equal(1.3, summary.SunshineDurationHours);
+        Assert.Contains("08–16 Uhr", summary.Tooltip);
+        Assert.Contains("Regenwahrscheinlichkeit: bis 65 % (stündlich)", summary.Tooltip);
+        Assert.Contains($"Sonnenschein: {summary.SunshineDurationHours:0.#} h", summary.Tooltip);
+    }
+
+    [Fact]
+    public void From_AmtlicheGewitterwarnung_PraegtSymbolUndTooltip()
+    {
+        var snapshot = Snapshot(Hour(10, cloud: 20));
+        snapshot.Warnings.Add(new WeatherWarning
+        {
+            Identifier = "w1", Event = "GEWITTER", Headline = "Amtliche Warnung vor Gewitter",
+            Instruction = "Aufenthalt im Freien vermeiden.", Severity = "Severe",
+            Onset = Day.ToDateTime(new TimeOnly(12, 0)), Expires = Day.ToDateTime(new TimeOnly(16, 0)),
+        });
+
+        var summary = SchoolDayWeatherSummary.From(snapshot, Day);
+
+        Assert.Equal(SchoolDayWeatherKind.Thunderstorm, summary!.Kind);
+        Assert.Contains("Amtliche Warnung", summary.Tooltip);
+        Assert.Contains("Aufenthalt im Freien", summary.Tooltip);
+    }
+
+    [Fact]
+    public void From_RegenSummiertStundenUndZeigtTemperaturspanne()
+    {
+        var snapshot = Snapshot(
+            Hour(8, temperature: 12, rain: 0.1),
+            Hour(12, temperature: 17, rain: 0.4));
+
+        var summary = SchoolDayWeatherSummary.From(snapshot, Day);
+
+        Assert.Equal(SchoolDayWeatherKind.Rain, summary!.Kind);
+        Assert.Equal(0.5, summary.PrecipitationMm);
+        Assert.Contains("12–17 °C", summary.Tooltip);
+    }
+
+    [Fact]
+    public void WarningTouchesDate_MehrtaegigeVorwarnung_TrifftAlleUeberlapptenTage()
+    {
+        var warning = new WeatherWarning
+        {
+            Onset = Day.ToDateTime(new TimeOnly(18, 0)),
+            Expires = Day.AddDays(2).ToDateTime(new TimeOnly(8, 0)),
+        };
+
+        Assert.True(SchoolDayWeatherSummary.WarningTouchesDate(warning, Day.AddDays(1)));
+        Assert.False(SchoolDayWeatherSummary.WarningTouchesDate(warning, Day.AddDays(3)));
+    }
+
+    [Fact]
+    public void WeekCellItem_WetterOderWarnung_AktiviertGemeinsameHoverFlaeche()
+    {
+        var cell = WeekCellItem.WeekdayHeader(DayOfWeek.Monday, Day, false);
+        Assert.False(cell.HasWeatherInformation);
+
+        cell.SetWeather(SchoolDayWeatherSummary.From(Snapshot(Hour(10)), Day), []);
+        Assert.True(cell.HasWeatherInformation);
+
+        cell.SetWeather(null, [new WeatherWarning { Headline = "Amtliche Warnung" }]);
+        Assert.True(cell.HasWeatherInformation);
+        Assert.Contains("Amtliche Warnung", cell.WeatherTooltip);
+    }
+
+    private static WeatherSnapshot Snapshot(params WeatherForecastHour[] hours) => new()
+    {
+        RetrievedAt = DateTime.UtcNow,
+        Forecast = hours.ToList(),
+    };
+
+    private static WeatherForecastHour Hour(int hour, int? code = 0, double? temperature = 20,
+        double? rain = 0, double? gust = 20, double? cloud = 20,
+        double? probability = null, double? sunshineMinutes = null) => new()
+    {
+        ValidAt = Day.ToDateTime(new TimeOnly(hour, 0)), WeatherCode = code,
+        TemperatureC = temperature, PrecipitationMm = rain, WindGustKmh = gust,
+        CloudCoverPercent = cloud, PrecipitationProbabilityPercent = probability,
+        SunshineDurationMinutes = sunshineMinutes,
+    };
+}

LehrerApp.Desktop.Tests/SeatingPlanViewModelTests.cs

@@ -472,6 +472,7 @@ public sealed class SeatingPlanViewModelTests
         vm.SetRatingByNumber(5);
         vm.ApplyAttendanceShortcut(1, clear: false);
         vm.ApplyHomeworkShortcut(7, clear: false);
+        vm.ApplyDayHighlightShortcut(1, clear: false);
 
         var session = Assert.Single(sessions.GetByGroup(groupId));
         Assert.Equal(DateOnly.FromDateTime(DateTime.Today), session.Date);
@@ -481,6 +482,56 @@ public sealed class SeatingPlanViewModelTests
         Assert.Equal(AttendanceStatus.Present, entry.Attendance);
         Assert.Equal(HomeworkStatus.MissingOpen, entry.Homework);
         Assert.True(entry.HomeworkMissing);
+        Assert.Equal(DayHighlightKind.Standout, entry.DayHighlight);
+    }
+
+    [Fact]
+    public void SitzplatzBewertung_TagesflaggeKannWiederGeloeschtWerden()
+    {
+        var groupId = Guid.NewGuid();
+        var studentId = Guid.NewGuid();
+        var sessions = new FakeSessions([]);
+        var entries = new FakeEntries();
+        var vm = new SeatAssessmentViewModel(sessions, entries, new FakeAspects(),
+            groupId, studentId, "Beispiel, Anna", canEdit: true);
+
+        vm.ApplyDayHighlightShortcut(3, clear: false); // aus Versehen "Schlechter Tag" gesetzt
+        vm.ApplyDayHighlightShortcut(null, clear: true);
+
+        var session = Assert.Single(sessions.GetByGroup(groupId));
+        var entry = entries.GetBySessionAndStudent(session.Id, studentId)!;
+        Assert.Null(entry.DayHighlight);
+        Assert.Equal("Keine Markierung", vm.DayHighlightLabel);
+        Assert.All(vm.DayHighlightChoices, c => Assert.Equal(c.Kind is null, c.IsSelected));
+    }
+
+    [Fact]
+    public void SitzplatzBewertung_SchlaegtQuantitaetAusStrichlisteVor()
+    {
+        var groupId = Guid.NewGuid();
+        var studentId = Guid.NewGuid();
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var session = new ParticipationSession { GroupId = groupId, Date = today };
+        var sessions = new FakeSessions([session]);
+        var entries = new FakeEntries();
+        entries.Add(new ParticipationEntry { SessionId = session.Id, StudentId = studentId, RaisedHandCount = 3 });
+
+        var vm = new SeatAssessmentViewModel(sessions, entries, new FakeAspects(),
+            groupId, studentId, "Beispiel, Anna", canEdit: true);
+
+        var quantityRow = vm.AspectRows.Single(r => r.Key == "quantity");
+        Assert.True(quantityRow.HasSuggestion);
+        Assert.Equal(0, quantityRow.SuggestedValue); // 3 gemeldet -> "∼" laut ParticipationCountSuggestion
+        Assert.Contains("3× gemeldet", quantityRow.SuggestionLabel);
+
+        var qualityRow = vm.AspectRows.Single(r => r.Key == "quality");
+        Assert.False(qualityRow.HasSuggestion);
+
+        quantityRow.ApplySuggestionCommand.Execute(null);
+
+        Assert.Equal(0, quantityRow.Value);
+        var updatedEntry = entries.GetBySessionAndStudent(session.Id, studentId)!;
+        Assert.Equal(0, updatedEntry.Ratings.Single(r => r.Key == "quantity").Value);
     }
 
     [Fact]
@@ -517,6 +568,60 @@ public sealed class SeatingPlanViewModelTests
         Assert.Null(vm.SelectedSession);
     }
 
+    [Fact]
+    public void TallyRaisedHand_ErhoehtNurGemeldetZaehler()
+    {
+        var groupId = Guid.NewGuid();
+        var student = new Student { FirstName = "Anna", LastName = "A" };
+        var plan = new SeatingPlan
+        {
+            GroupId = groupId, Name = "Standard", Rows = 1, Columns = 1,
+            Assignments = [new SeatAssignment { StudentId = student.Id }],
+        };
+        var sessions = new FakeSessions([]);
+        var entries = new FakeEntries();
+        var vm = new SeatingPlanTabViewModel(new FakeSeatingPlans([plan]), new FakeStudents([student]),
+            new FakeMemberships([new GroupMembership { GroupId = groupId, StudentId = student.Id }]),
+            sessions, entries, new FakeAspects());
+        vm.Initialize(groupId, isReadOnly: false);
+        var seat = vm.Seats.Single();
+
+        seat.TallyRaisedHandCommand.Execute(null);
+        seat.TallyRaisedHandCommand.Execute(null);
+
+        Assert.Equal(2, seat.RaisedHandCount);
+        Assert.Equal(0, seat.CalledOnCount);
+        var session = Assert.Single(sessions.GetByGroup(groupId));
+        var entry = entries.GetBySessionAndStudent(session.Id, student.Id)!;
+        Assert.Equal(2, entry.RaisedHandCount);
+        Assert.Equal(0, entry.CalledOnCount);
+    }
+
+    [Fact]
+    public void TallyCalledOn_ErhoehtBeideZaehler()
+    {
+        var groupId = Guid.NewGuid();
+        var student = new Student { FirstName = "Anna", LastName = "A" };
+        var plan = new SeatingPlan
+        {
+            GroupId = groupId, Name = "Standard", Rows = 1, Columns = 1,
+            Assignments = [new SeatAssignment { StudentId = student.Id }],
+        };
+        var sessions = new FakeSessions([]);
+        var entries = new FakeEntries();
+        var vm = new SeatingPlanTabViewModel(new FakeSeatingPlans([plan]), new FakeStudents([student]),
+            new FakeMemberships([new GroupMembership { GroupId = groupId, StudentId = student.Id }]),
+            sessions, entries, new FakeAspects());
+        vm.Initialize(groupId, isReadOnly: false);
+        var seat = vm.Seats.Single();
+
+        seat.TallyRaisedHandCommand.Execute(null); // erste Meldung, nicht drangekommen
+        seat.TallyCalledOnCommand.Execute(null);   // zweite Meldung, drangekommen
+
+        Assert.Equal(2, seat.RaisedHandCount);
+        Assert.Equal(1, seat.CalledOnCount);
+    }
+
     [Fact]
     public async Task AssessStudent_LegtErstBeiTatsaechlicherBewertungEineSitzungAn()
     {
@@ -543,6 +648,50 @@ public sealed class SeatingPlanViewModelTests
         Assert.Equal(session.Id, vm.SelectedSession?.Id);
     }
 
+    [Fact]
+    public async Task AssessStudent_SitzungBereitsUeberAndereInstanzVerknuepft_LegtKeineZweiteAn()
+    {
+        // Regressionstest: Der Unterrichtsmodus läuft auf einer eigenen, per DI frisch aufgelösten
+        // SeatingPlanTabViewModel-Instanz (TimetableView.ShowTeachingMode), getrennt von der
+        // Instanz im Sitzplan-Tab der Kursübersicht — beide teilen sich nur das Repository. Wurde
+        // (wie hier simuliert) die Sitzung bereits über den Unterrichtsmodus mit der Stunde
+        // verknüpft, bevor im echten Sitzplan-Tab bewertet wird, darf letzterer keine zweite,
+        // unverknüpfte "Sitzplan"-Sitzung für denselben Tag anlegen.
+        var groupId = Guid.NewGuid();
+        var student = new Student { FirstName = "Anna", LastName = "A" };
+        var plan = new SeatingPlan
+        {
+            GroupId = groupId, Name = "Standard", Rows = 1, Columns = 1,
+            Assignments = [new SeatAssignment { StudentId = student.Id }],
+        };
+        var sessions = new FakeSessions([]);
+        var memberships = new FakeMemberships([new GroupMembership { GroupId = groupId, StudentId = student.Id }]);
+
+        // Instanz A: Sitzplan-Tab der Kursübersicht, bereits initialisiert (kein SelectedSession).
+        var tabVm = new SeatingPlanTabViewModel(new FakeSeatingPlans([plan]), new FakeStudents([student]),
+            memberships, sessions, new FakeEntries(), new FakeAspects());
+        tabVm.Initialize(groupId, isReadOnly: false);
+        tabVm.OnAssessStudent = _ => Task.CompletedTask;
+
+        // Instanz B: eigene, frische Instanz wie im Unterrichtsmodus — verknüpft die Sitzung mit
+        // der Stunde, ohne dass Instanz A davon erfährt.
+        var lesson = new Lesson { GroupId = groupId, Date = DateOnly.FromDateTime(DateTime.Today), Topic = "Redox" };
+        var teachingModeVm = new SeatingPlanTabViewModel(new FakeSeatingPlans([plan]), new FakeStudents([student]),
+            memberships, sessions, new FakeEntries(), new FakeAspects());
+        teachingModeVm.Initialize(groupId, isReadOnly: false);
+        teachingModeVm.SelectOrCreateSessionForLesson(lesson);
+
+        var linked = Assert.Single(sessions.GetByGroup(groupId));
+        Assert.Equal(lesson.Id, linked.LessonId);
+
+        await tabVm.AssessStudent(tabVm.Seats.Single());
+
+        var session = Assert.Single(sessions.GetByGroup(groupId));
+        Assert.Equal(linked.Id, session.Id);
+        Assert.Equal(lesson.Id, session.LessonId);
+        Assert.Equal(session.Id, tabVm.SelectedSession?.Id);
+    }
+
     [Fact]
     public void ShuffleSeats_ErzeugtNeuenPlanMitVertauschtenPlaetzenUndBehaeltDenUrsprungsplan()
     {

LehrerApp.Desktop.Tests/SettingsViewModelTests.cs

@@ -7,6 +7,7 @@ using LehrerApp.Sync;
 using LehrerApp.Sync.Models;
 using System.Linq;
 using Xunit;
+using LehrerApp.Templating;
 
 namespace LehrerApp.Desktop.Tests;
 
@@ -28,12 +29,13 @@ public sealed class SettingsViewModelTests
         return new SettingsViewModel(
             subjects ?? new FakeSubjects([]), competencyDomains ?? new FakeCompetencyDomains(), new FakeGradingKeyTemplates(),
             new FakeSchemes(), new GradingService(), new BackupService(tempPath),
+            new BackupSettingsService(tempPath),
             new DatabaseEncryptionService(), new AppLockService(tempPath),
             new LiteDbContext(new MemoryStream()), new PrivacySettingsService(tempPath),
             new FakeDocumentation(), new FakeStudents([]), new FakeShorthandCodes([]),
             holidays ?? new FakeSchoolHolidays(), new SchoolCalendarSettingsService(tempPath),
             new PeriodScheduleService(tempPath), supervisionDuties ?? new FakeSupervisionDuties(),
-            new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
+            new TemplateStore(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
             TestSupport.BuildWebUntisSettingsService(),
             TestSupport.BuildAnnualPlanSettingsService(),
             TestSupport.BuildSyncSettingsService(), TestSupport.BuildSyncAuthService(),
@@ -314,11 +316,12 @@ public sealed class SettingsViewModelTests
         var vm = new SettingsViewModel(
             new FakeSubjects([]), new FakeCompetencyDomains(), new FakeGradingKeyTemplates(),
             new FakeSchemes(), new GradingService(), new BackupService(tempPath),
+            new BackupSettingsService(tempPath),
             new DatabaseEncryptionService(), new AppLockService(tempPath),
             new LiteDbContext(new MemoryStream()), new PrivacySettingsService(tempPath),
             new FakeDocumentation(), new FakeStudents([]), new FakeShorthandCodes([]),
             new FakeSchoolHolidays(), calendarSettings, new PeriodScheduleService(tempPath),
-            new FakeSupervisionDuties(), new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
+            new FakeSupervisionDuties(), new TemplateStore(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
             TestSupport.BuildWebUntisSettingsService(),
             TestSupport.BuildAnnualPlanSettingsService(),
             TestSupport.BuildSyncSettingsService(), TestSupport.BuildSyncAuthService(), TestSupport.BuildEventQueue(),
@@ -341,11 +344,12 @@ public sealed class SettingsViewModelTests
         var vm = new SettingsViewModel(
             new FakeSubjects([]), new FakeCompetencyDomains(), new FakeGradingKeyTemplates(),
             new FakeSchemes(), new GradingService(), new BackupService(tempPath),
+            new BackupSettingsService(tempPath),
             new DatabaseEncryptionService(), new AppLockService(tempPath),
             new LiteDbContext(new MemoryStream()), new PrivacySettingsService(tempPath),
             new FakeDocumentation(), new FakeStudents([]), new FakeShorthandCodes([]),
             new FakeSchoolHolidays(), new SchoolCalendarSettingsService(tempPath), periodSchedule,
-            new FakeSupervisionDuties(), new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
+            new FakeSupervisionDuties(), new TemplateStore(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
             TestSupport.BuildWebUntisSettingsService(),
             TestSupport.BuildAnnualPlanSettingsService(),
             TestSupport.BuildSyncSettingsService(), TestSupport.BuildSyncAuthService(), TestSupport.BuildEventQueue(),
@@ -372,11 +376,12 @@ public sealed class SettingsViewModelTests
         var vm = new SettingsViewModel(
             new FakeSubjects([]), new FakeCompetencyDomains(), new FakeGradingKeyTemplates(),
             new FakeSchemes(), new GradingService(), new BackupService(tempPath),
+            new BackupSettingsService(tempPath),
             new DatabaseEncryptionService(), new AppLockService(tempPath),
             new LiteDbContext(new MemoryStream()), new PrivacySettingsService(tempPath),
             new FakeDocumentation(), new FakeStudents([]), new FakeShorthandCodes([]),
             new FakeSchoolHolidays(), new SchoolCalendarSettingsService(tempPath), periodSchedule,
-            new FakeSupervisionDuties(), new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
+            new FakeSupervisionDuties(), new TemplateStore(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
             TestSupport.BuildWebUntisSettingsService(),
             TestSupport.BuildAnnualPlanSettingsService(),
             TestSupport.BuildSyncSettingsService(), TestSupport.BuildSyncAuthService(), TestSupport.BuildEventQueue(),

LehrerApp.Desktop.Tests/StudentListViewModelTests.cs

@@ -51,6 +51,18 @@ public class StudentListViewModelTests
         Assert.Equal("M", vm.Students.Single(s => s.Id == _ben.Id).AvatarLabel);
     }
 
+    [Fact]
+    public void SucheOhneTreffer_LiefertHilfreichenLeerzustand()
+    {
+        var vm = BuildViewModel();
+
+        vm.SearchText = "nicht vorhanden";
+
+        Assert.True(vm.HasNoStudents);
+        Assert.False(vm.HasStudents);
+        Assert.Contains("Suche", vm.EmptyListMessage);
+    }
+
     private StudentListViewModel BuildViewModel() => new(
         new FakeStudents([_anna, _ben]),
         new FakeGroups([_group]),

LehrerApp.Desktop.Tests/StudentPerformanceOverviewViewModelTests.cs

@@ -0,0 +1,146 @@
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Desktop.ViewModels.Groups;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+/// Tests für den Schüler-Leistungsüberblick (Nutzer-Feedback): Klausuren/Mitarbeit/Sonstige
+/// im Überblick, berechnete Zeugnisnote, Zielnoten- und Was-wäre-wenn-Rechner sowie der
+/// Bewerter-/Schülermodus-Unterschied (Kursdurchschnitt, Bearbeitbarkeit).
+public sealed class StudentPerformanceOverviewViewModelTests
+{
+    private static readonly Guid GroupId = Guid.NewGuid();
+    private static readonly Guid StudentId = Guid.NewGuid();
+    private static readonly Guid OtherStudentId = Guid.NewGuid();
+
+    private static StudentPerformanceOverviewViewModel BuildViewModel(
+        FakeExams? exams = null, FakeResults? results = null, FakeGrades? grades = null,
+        FakeSchemes? schemes = null, GradingSystem system = GradingSystem.Grades1To6)
+    {
+        var scheme = new GradingScheme { ExamsPercent = 50, ParticipationPercent = 40, OtherPercent = 10 };
+        var schemesRepo = schemes ?? new FakeSchemes();
+        if (schemes is null) schemesRepo.SetForGroup(GroupId, scheme);
+
+        return new StudentPerformanceOverviewViewModel(
+            grades ?? new FakeGrades(), exams ?? new FakeExams([]), results ?? new FakeResults(),
+            new FakeMemberships([]), schemesRepo, new GradingService(),
+            GroupId, StudentId, GroupType.Class, system, "Beispiel, Anna", "Testkurs", "2025/26");
+    }
+
+    [Fact]
+    public void ExamRows_ZeigtEigeneNoteUndKursdurchschnitt()
+    {
+        var exam = new Exam { Id = Guid.NewGuid(), GroupId = GroupId, Title = "K1", Date = new DateOnly(2025, 9, 10) };
+        var exams = new FakeExams([exam]);
+        var results = new FakeResults();
+        results.Add(new ExamResult { ExamId = exam.Id, StudentId = StudentId, Grade = "2" });
+        results.Add(new ExamResult { ExamId = exam.Id, StudentId = OtherStudentId, Grade = "4" });
+
+        var vm = BuildViewModel(exams, results);
+
+        var row = Assert.Single(vm.ExamRows);
+        Assert.Equal("2", row.OwnGradeDisplay);
+        Assert.Equal("3.0", row.ClassAverageDisplay);
+    }
+
+    [Fact]
+    public void ExamHistory_ZeigtEigenenVerlaufUndMarkiertNotenabfall()
+    {
+        var exam1 = new Exam { Id = Guid.NewGuid(), GroupId = GroupId, Title = "K1", Date = new DateOnly(2025, 9, 10) };
+        var exam2 = new Exam { Id = Guid.NewGuid(), GroupId = GroupId, Title = "K2", Date = new DateOnly(2025, 9, 24) };
+        var exams = new FakeExams([exam1, exam2]);
+        var results = new FakeResults();
+        results.Add(new ExamResult { ExamId = exam1.Id, StudentId = StudentId, Grade = "2" });
+        results.Add(new ExamResult { ExamId = exam2.Id, StudentId = StudentId, Grade = "5" }); // Abfall + mangelhaft
+
+        var vm = BuildViewModel(exams, results);
+
+        Assert.Equal(2, vm.ExamHistory.Points.Count);
+        Assert.False(vm.ExamHistory.Points[0].IsWarning);
+        Assert.True(vm.ExamHistory.Points[1].IsWarning);
+        Assert.Contains("Abfall", vm.ExamHistory.Points[1].WarningText);
+        Assert.Contains("Versetzungsgefährdung", vm.ExamHistory.Points[1].WarningText);
+        Assert.True(vm.ExamHistory.Points[1].BarHeight < vm.ExamHistory.Points[0].BarHeight);
+    }
+
+    [Fact]
+    public void AktuelleZeugnisnote_KombiniertAlleDreiBereiche()
+    {
+        var exam = new Exam { Id = Guid.NewGuid(), GroupId = GroupId, Title = "K1", Date = new DateOnly(2025, 9, 10) };
+        var exams = new FakeExams([exam]);
+        var results = new FakeResults();
+        results.Add(new ExamResult { ExamId = exam.Id, StudentId = StudentId, Grade = "2" });
+        var grades = new FakeGrades();
+        grades.Add(new Grade { StudentId = StudentId, GroupId = GroupId, Category = GradeCategory.Participation,
+            Date = new DateOnly(2025, 9, 5), Value = "3" });
+        grades.Add(new Grade { StudentId = StudentId, GroupId = GroupId, Category = GradeCategory.Other,
+            Date = new DateOnly(2025, 9, 5), Value = "1" });
+
+        var vm = BuildViewModel(exams, results, grades);
+
+        // (2*50 + 3*40 + 1*10) / 100 = 2.3 -> kaufmännisch 2
+        Assert.Equal("Note 2", vm.CurrentReportGradeDisplay);
+    }
+
+    [Fact]
+    public void Zielnote_BerechnetNoetigenKlausurschnitt()
+    {
+        var grades = new FakeGrades();
+        grades.Add(new Grade { StudentId = StudentId, GroupId = GroupId, Category = GradeCategory.Participation,
+            Date = new DateOnly(2025, 9, 5), Value = "3" });
+        grades.Add(new Grade { StudentId = StudentId, GroupId = GroupId, Category = GradeCategory.Other,
+            Date = new DateOnly(2025, 9, 5), Value = "2" });
+        var vm = BuildViewModel(grades: grades);
+
+        vm.TargetGradeText = "2";
+        vm.TargetBucketName = "Klausuren";
+
+        // Ziel 2,0 = (x*50 + 3*40 + 2*10)/100 => 200 = 50x+120+20 => x = 1,2
+        Assert.Contains("1.2", vm.TargetResultDisplay);
+    }
+
+    [Fact]
+    public void WasWaereWenn_ZeigtZeugnisnoteMitZusaetzlicherKlausurAn()
+    {
+        var exam = new Exam { Id = Guid.NewGuid(), GroupId = GroupId, Title = "K1", Date = new DateOnly(2025, 9, 10) };
+        var exams = new FakeExams([exam]);
+        var results = new FakeResults();
+        results.Add(new ExamResult { ExamId = exam.Id, StudentId = StudentId, Grade = "2" });
+        var grades = new FakeGrades();
+        grades.Add(new Grade { StudentId = StudentId, GroupId = GroupId, Category = GradeCategory.Participation,
+            Date = new DateOnly(2025, 9, 5), Value = "2" });
+
+        var vm = BuildViewModel(exams, results, grades);
+
+        vm.WhatIfExamGradeText = "6";
+
+        // Klausuren neu: (2+6)/2=4 (50%), Mitarbeit 2 (40%, Sonstige fehlt) -> (4*50+2*40)/90 = 3,11 -> kaufm. 3
+        Assert.Contains("3", vm.WhatIfResultDisplay);
+    }
+
+    [Fact]
+    public void SaveCommand_AufMitarbeitszeile_SpeichertUndAktualisiertDurchschnitt()
+    {
+        var grades = new FakeGrades();
+        var grade = new Grade { StudentId = StudentId, GroupId = GroupId, Category = GradeCategory.Participation,
+            Date = new DateOnly(2025, 9, 5), Value = "3" };
+        grades.Add(grade);
+        var vm = BuildViewModel(grades: grades);
+
+        var row = Assert.Single(vm.ParticipationRows);
+        row.Value = "1";
+        row.SaveCommand.Execute(null);
+
+        Assert.Equal("1.0", vm.ParticipationAverageDisplay);
+        Assert.Equal("1", grades.GetByStudentAndGroup(StudentId, GroupId).Single().Value);
+    }
+
+    [Fact]
+    public void OhneWerteImZeitraum_ZeigtHinweisStattZeugnisnote()
+    {
+        var vm = BuildViewModel();
+
+        Assert.Contains("Noch nicht berechenbar", vm.CurrentReportGradeDisplay);
+    }
+}

LehrerApp.Desktop.Tests/TeachingModeViewModelTests.cs

@@ -13,6 +13,17 @@ public sealed class TeachingModeViewModelTests
             new FakeStudents(students ?? []), new FakeMemberships(memberships ?? []),
             sessions ?? new FakeSessions([]), new FakeEntries(), new FakeAspects());
 
+    /// Dieselben Fakes wie <see cref="BuildSeatingPlan"/>, aber für ParticipationTabViewModel —
+    /// beide brauchen eigene IParticipationSessionRepository/IParticipationRepository-Instanzen
+    /// im Produktivcode (siehe TeachingModeWindow-Kommentar zu ReloadSeatBadgesFromRepository),
+    /// hier reicht für die Tests aber eine gemeinsame FakeSessions-Instanz, damit beide
+    /// ViewModels dieselbe verknüpfte Sitzung sehen.
+    private static ParticipationTabViewModel BuildParticipation(LearningGroup group,
+        FakeSessions? sessions = null) =>
+        new(sessions ?? new FakeSessions([]), new FakeEntries(), new FakeAspects(),
+            new FakeStudents([]), new FakeMemberships([]), new FakeGroups([group]),
+            new FakeCompetencyDomains());
+
     [Fact]
     public void Konstruktor_LaedtVerlaufsplanUndInitialisiertSitzplanFuerDieGruppe()
     {
@@ -24,7 +35,8 @@ public sealed class TeachingModeViewModelTests
         };
         var seatingPlan = BuildSeatingPlan(group.Id);
 
-        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]), seatingPlan);
+        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]),
+            new FakeLessons(), seatingPlan, BuildParticipation(group));
 
         Assert.Equal("Q1 Chemie", vm.GroupName);
         Assert.Equal("Redox", vm.LessonInfo.Topic);
@@ -41,13 +53,37 @@ public sealed class TeachingModeViewModelTests
         var sessions = new FakeSessions([]);
         var seatingPlan = BuildSeatingPlan(group.Id, sessions);
 
-        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]), seatingPlan);
+        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]),
+            new FakeLessons(), seatingPlan, BuildParticipation(group, sessions));
 
         var created = Assert.Single(sessions.GetByGroup(group.Id));
         Assert.Equal(lesson.Id, created.LessonId);
         Assert.Equal(vm.SeatingPlan.SelectedSession?.Id, created.Id);
     }
 
+    /// Nutzer-Feedback: Schnellbewertungs-Dialoge (Mitarbeit, Anwesenheit/Hausaufgabe) sollen sich
+    /// im Unterrichtsmodus direkt öffnen lassen — das setzt voraus, dass die dafür verwendete
+    /// ParticipationTabViewModel-Instanz von Anfang an auf der zu dieser Stunde gehörenden
+    /// Sitzung steht, nicht auf einer beliebigen anderen Sitzung der Gruppe.
+    [Fact]
+    public void Konstruktor_SelektiertDieselbeSitzungAuchInDerParticipationViewModel()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        var lesson = new Lesson
+        { GroupId = group.Id, Date = DateOnly.FromDateTime(DateTime.Today), Topic = "Redox" };
+        var otherSession = new ParticipationSession
+        { GroupId = group.Id, Date = lesson.Date.AddDays(-1), Comment = "Andere Stunde" };
+        var sessions = new FakeSessions([otherSession]);
+        var seatingPlan = BuildSeatingPlan(group.Id, sessions);
+
+        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]),
+            new FakeLessons(), seatingPlan, BuildParticipation(group, sessions));
+
+        Assert.NotNull(vm.SeatingPlan.SelectedSession);
+        Assert.Equal(vm.SeatingPlan.SelectedSession!.Id, vm.Participation.SelectedSession?.Id);
+        Assert.NotEqual(otherSession.Id, vm.Participation.SelectedSession?.Id);
+    }
+
     [Fact]
     public void Konstruktor_BereitsExistierendeVerknuepfteSitzung_WirdWiederverwendet()
     {
@@ -59,7 +95,8 @@ public sealed class TeachingModeViewModelTests
         var sessions = new FakeSessions([existing]);
         var seatingPlan = BuildSeatingPlan(group.Id, sessions);
 
-        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]), seatingPlan);
+        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]),
+            new FakeLessons(), seatingPlan, BuildParticipation(group, sessions));
 
         Assert.Single(sessions.GetByGroup(group.Id));
         Assert.Equal(existing.Id, vm.SeatingPlan.SelectedSession?.Id);
@@ -75,8 +112,92 @@ public sealed class TeachingModeViewModelTests
         { GroupId = group.Id, Date = DateOnly.FromDateTime(DateTime.Today), Topic = "Redox" };
         var seatingPlan = BuildSeatingPlan(group.Id);
 
-        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]), seatingPlan);
+        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]),
+            new FakeLessons(), seatingPlan, BuildParticipation(group));
 
         Assert.False(vm.SeatingPlan.IsEditable);
     }
+
+    // ── Hausaufgabe: letzte Stunde ansehen/abhaken, aktuelle einsehen/ändern ─────
+
+    [Fact]
+    public void Konstruktor_FindetHausaufgabeDerVorherigenStunde()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var previous = new Lesson
+        {
+            GroupId = group.Id, Date = today.AddDays(-7), Topic = "Säuren",
+            Homework = "S. 42, Aufgabe 3", HomeworkChecked = false,
+        };
+        var lesson = new Lesson { GroupId = group.Id, Date = today, Topic = "Redox" };
+        var lessons = new FakeLessons();
+        lessons.Add(previous);
+        var seatingPlan = BuildSeatingPlan(group.Id);
+
+        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]),
+            lessons, seatingPlan, BuildParticipation(group));
+
+        Assert.True(vm.Homework.HasPreviousHomework);
+        Assert.Equal("S. 42, Aufgabe 3", vm.Homework.PreviousHomeworkText);
+        Assert.Contains("Säuren", vm.Homework.PreviousLessonLabel);
+        Assert.False(vm.Homework.PreviousHomeworkChecked);
+    }
+
+    [Fact]
+    public void Konstruktor_IgnoriertVorherigeStundeOhneHausaufgabe()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var previous = new Lesson { GroupId = group.Id, Date = today.AddDays(-7), Topic = "Säuren" };
+        var lesson = new Lesson { GroupId = group.Id, Date = today, Topic = "Redox" };
+        var lessons = new FakeLessons();
+        lessons.Add(previous);
+        var seatingPlan = BuildSeatingPlan(group.Id);
+
+        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]),
+            lessons, seatingPlan, BuildParticipation(group));
+
+        Assert.False(vm.Homework.HasPreviousHomework);
+    }
+
+    [Fact]
+    public void PreviousHomeworkChecked_SpeichertSofortAnDerVorherigenStunde()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var previous = new Lesson
+        { GroupId = group.Id, Date = today.AddDays(-7), Topic = "Säuren", Homework = "S. 42" };
+        var lesson = new Lesson { GroupId = group.Id, Date = today, Topic = "Redox" };
+        var lessons = new FakeLessons();
+        lessons.Add(previous);
+        var seatingPlan = BuildSeatingPlan(group.Id);
+        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]),
+            lessons, seatingPlan, BuildParticipation(group));
+
+        vm.Homework.PreviousHomeworkChecked = true;
+
+        var saved = Assert.Single(lessons.GetByGroupAndRange(group.Id, today.AddDays(-120), today.AddDays(-1)));
+        Assert.True(saved.HomeworkChecked);
+    }
+
+    [Fact]
+    public void SaveCurrentHomework_SchreibtAufDieAktuelleStunde()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        var lesson = new Lesson
+        { GroupId = group.Id, Date = DateOnly.FromDateTime(DateTime.Today), Topic = "Redox" };
+        var lessons = new FakeLessons();
+        lessons.Add(lesson);
+        var seatingPlan = BuildSeatingPlan(group.Id);
+        var vm = new TeachingModeViewModel(lesson, group, new FakeAlternativeLessonPaths([]),
+            lessons, seatingPlan, BuildParticipation(group));
+
+        vm.Homework.CurrentHomework = "AB 7 fertigstellen";
+        vm.Homework.SaveCurrentHomeworkCommand.Execute(null);
+
+        var saved = Assert.Single(lessons.GetByGroupAndRange(group.Id, lesson.Date, lesson.Date));
+        Assert.Equal("AB 7 fertigstellen", saved.Homework);
+        Assert.Equal("Gespeichert.", vm.Homework.SaveStatus);
+    }
 }

LehrerApp.Desktop.Tests/TimetableViewModelTests.cs

@@ -14,10 +14,11 @@ public sealed class TimetableViewModelTests
         FakeSubjects? subjects = null, FakeLessons? lessons = null, FakeExams? exams = null,
         SchoolCalendarSettingsService? calendarSettings = null,
         FakeSupervisionDuties? supervisionDuties = null, FakeSubstitutionEntries? substitutions = null,
-        FakeUntisSlotMappings? untisMappings = null, WebUntisSettingsService? untisSettings = null)
+        FakeUntisSlotMappings? untisMappings = null, WebUntisSettingsService? untisSettings = null,
+        PeriodScheduleService? periodSchedule = null)
     {
-        // Bewusst kein "using": SchoolCalendarSettingsService liest den Pfad nur bei Bedarf
+        // Bewusst kein "using": SchoolCalendarSettingsService/PeriodScheduleService lesen den Pfad
-        // (SetState), das Verzeichnis muss über die Lebensdauer des ViewModels bestehen bleiben.
+        // nur bei Bedarf, das Verzeichnis muss über die Lebensdauer des ViewModels bestehen bleiben.
         var tempPath = System.IO.Path.Combine(
             System.IO.Path.GetTempPath(), $"lehrerapp-timetablevm-tests-{Guid.NewGuid():N}");
         Directory.CreateDirectory(tempPath);
@@ -28,7 +29,8 @@ public sealed class TimetableViewModelTests
             calendarSettings ?? new SchoolCalendarSettingsService(tempPath),
             new PublicHolidayService(), new SchoolYearService(),
             supervisionDuties ?? new FakeSupervisionDuties(), substitutions ?? new FakeSubstitutionEntries(),
-            untisMappings ?? new FakeUntisSlotMappings(), untisSettings ?? TestSupport.BuildWebUntisSettingsService());
+            untisMappings ?? new FakeUntisSlotMappings(), untisSettings ?? TestSupport.BuildWebUntisSettingsService(),
+            periodSchedule ?? new PeriodScheduleService(tempPath));
     }
 
     /// Nächstes Datum ab (inkl.) <paramref name="from"/>, das auf einen Wochentag Mo-Fr fällt —
@@ -275,7 +277,23 @@ public sealed class TimetableViewModelTests
 
         Assert.Equal(group.Id, navigatedTo);
         Assert.False(viewerOpened);
-        Assert.Equal("Zur Lerngruppe", vm.TodayItems[0].OpenButtonLabel);
+        Assert.Equal("Stunde anlegen", vm.TodayItems[0].OpenButtonLabel);
+    }
+
+    [Fact]
+    public async Task OpenTodayLesson_OhneLesson_StartetDirektanlageMitExaktemTermin()
+    {
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = today.DayOfWeek, PeriodNumber = 4 });
+        var vm = BuildViewModel(slots, new FakeGroups([group]));
+        TimetableLessonRequest? requested = null;
+        vm.OnCreateLesson = request => { requested = request; return Task.CompletedTask; };
+
+        await vm.OpenTodayLessonCommand.ExecuteAsync(vm.TodayItems[0]);
+
+        Assert.Equal(new TimetableLessonRequest(group.Id, today, 4), requested);
     }
 
     // ── Unterrichtsmodus (14.x) ────────────────────────────────────────────────
@@ -336,6 +354,88 @@ public sealed class TimetableViewModelTests
         Assert.Equal(lesson.Id, openedLesson?.Id);
     }
 
+    /// Nutzer-Feedback (zweite Runde): der Direktklick auf eine Wochenraster-Kachel soll
+    /// "einheitlicher" springen — bei einer Lesson HEUTE, während gerade Unterrichtszeit ist,
+    /// direkt in den Unterrichtsmodus statt in den (schreibgeschützten) Planungsviewer.
+    [Fact]
+    public async Task OpenWeekCell_LessonHeuteWaehrendUnterrichtszeit_OeffnetUnterrichtsmodus()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        // Bewusst nicht der reale DateTime.Today-Wochentag: an einem Sa/So gäbe es dafür keine
+        // Kachel im Mo-Fr-Raster. Stattdessen ein beliebiger Wochentag der laufenden Kalenderwoche
+        // (Kachel existiert immer), dessen Datum per VM.Clock als "heute" simuliert wird (siehe
+        // TimetableViewModel.Clock - genau für solche Tests eingeführt).
+        var weekday = DayOfWeek.Monday;
+        var lessonDate = DateInCurrentWeek(weekday);
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = weekday, PeriodNumber = 1 });
+        var lesson = new Lesson { GroupId = group.Id, Date = lessonDate, LessonNumber = 1, Topic = "Redox" };
+        var lessons = new FakeLessons();
+        lessons.Add(lesson);
+        var periodSchedule = BuildPeriodSchedule(1);
+        var vm = BuildViewModel(slots, new FakeGroups([group]), lessons: lessons, periodSchedule: periodSchedule);
+        // Gleiche Uhrzeit wie BuildPeriodSchedule (reales DateTime.Now), aber am simulierten
+        // "heutigen" Datum - die Stundenzeit-Prüfung (Uhrzeit) bleibt so unabhängig vom Datum.
+        vm.Clock = () => lessonDate.ToDateTime(TimeOnly.FromDateTime(DateTime.Now));
+        Lesson? teachingModeLesson = null;
+        Lesson? viewerLesson = null;
+        vm.OnOpenTeachingMode = l => { teachingModeLesson = l; return Task.CompletedTask; };
+        vm.OnOpenLessonViewer = l => { viewerLesson = l; return Task.CompletedTask; };
+
+        var cell = vm.WeekItems.Single(c => c.IsSlotCell && c.Weekday == weekday && c.PeriodNumber == 1);
+        await vm.OpenWeekCellCommand.ExecuteAsync(cell);
+
+        Assert.Equal(lesson.Id, teachingModeLesson?.Id);
+        Assert.Null(viewerLesson);
+    }
+
+    /// Dieselbe Stundenzeit passt, die Lesson liegt aber nicht heute — bleibt beim Viewer.
+    [Fact]
+    public async Task OpenWeekCell_LessonNichtHeuteTrotzPassenderUhrzeit_OeffnetViewer()
+    {
+        var group = new LearningGroup { Name = "Q1 Chemie" };
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var otherWeekday = today.DayOfWeek == DayOfWeek.Monday ? DayOfWeek.Tuesday : DayOfWeek.Monday;
+        var otherDate = DateInCurrentWeek(otherWeekday);
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = otherWeekday, PeriodNumber = 1 });
+        var lesson = new Lesson { GroupId = group.Id, Date = otherDate, LessonNumber = 1, Topic = "Redox" };
+        var lessons = new FakeLessons();
+        lessons.Add(lesson);
+        var periodSchedule = BuildPeriodSchedule(1);
+        var vm = BuildViewModel(slots, new FakeGroups([group]), lessons: lessons, periodSchedule: periodSchedule);
+        Lesson? teachingModeLesson = null;
+        Lesson? viewerLesson = null;
+        vm.OnOpenTeachingMode = l => { teachingModeLesson = l; return Task.CompletedTask; };
+        vm.OnOpenLessonViewer = l => { viewerLesson = l; return Task.CompletedTask; };
+
+        var cell = vm.WeekItems.Single(c => c.IsSlotCell && c.Weekday == otherWeekday && c.PeriodNumber == 1);
+        await vm.OpenWeekCellCommand.ExecuteAsync(cell);
+
+        Assert.Equal(lesson.Id, viewerLesson?.Id);
+        Assert.Null(teachingModeLesson);
+    }
+
+    /// Weites Zeitfenster um <paramref name="around"/> herum (±2 Stunden), damit der Test nicht an
+    /// die exakte Toleranz von TimetableViewModel.TeachingTimeTolerance gebunden ist.
+    /// Start UND Ende exakt auf "jetzt" statt eines künstlich breiteren Fensters (z.B. ganzer Tag
+    /// via TimeOnly.MinValue/MaxValue): TimetableViewModel.IsAroundTeachingTime addiert selbst
+    /// noch ±10 Minuten Toleranz (TeachingTimeTolerance) auf Start/Ende — ein zusätzliches, vom
+    /// Test vorgegebenes Fenster würde nahe Mitternacht durch die TimeOnly-Arithmetik (wrappt bei
+    /// 24 Uhr) selbst kippen. "Jetzt" als Start/Ende bleibt nur dann riskant, wenn der Test
+    /// zufällig innerhalb der letzten/ersten 10 Minuten des Tages läuft — dasselbe inhärente
+    /// Randproblem hätte dann auch die Produktion, kein Testartefakt.
+    private static PeriodScheduleService BuildPeriodSchedule(int periodNumber)
+    {
+        var tempPath = System.IO.Path.Combine(
+            System.IO.Path.GetTempPath(), $"lehrerapp-periodschedule-tests-{Guid.NewGuid():N}");
+        Directory.CreateDirectory(tempPath);
+        var service = new PeriodScheduleService(tempPath);
+        var now = TimeOnly.FromDateTime(DateTime.Now);
+        service.SetPeriods([new PeriodTimeEntry { PeriodNumber = periodNumber, Start = now, End = now }]);
+        return service;
+    }
+
     [Fact]
     public void OpenSettings_RuftOnNavigateToSettingsAuf()
     {
@@ -612,6 +712,31 @@ public sealed class TimetableViewModelTests
         Assert.Equal("1", period2.BadgeText);
     }
 
+    [Fact]
+    public void Load_Doppelstunde_ZeigtLessonThemaInBeidenKacheln_AuchOhnePhasenUndStundenraster()
+    {
+        var date = DateInCurrentWeek(DayOfWeek.Monday);
+        var group = new LearningGroup { Name = "10c" };
+        var slots = new FakeTimetableSlots();
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = date.DayOfWeek, PeriodNumber = 3 });
+        slots.Add(new TimetableSlot { GroupId = group.Id, Weekday = date.DayOfWeek, PeriodNumber = 4 });
+        var lesson = new Lesson
+        {
+            GroupId = group.Id, Date = date, LessonNumber = 3, Topic = "Werkstoffprüfung",
+            Phases = [],
+        };
+        var lessons = new FakeLessons();
+        lessons.Add(lesson);
+
+        var vm = BuildViewModel(slots, new FakeGroups([group]), lessons: lessons);
+
+        var first = vm.WeekItems.Single(c => c.IsSlotCell && c.Weekday == date.DayOfWeek && c.PeriodNumber == 3);
+        var second = vm.WeekItems.Single(c => c.IsSlotCell && c.Weekday == date.DayOfWeek && c.PeriodNumber == 4);
+        Assert.Equal("Werkstoffprüfung", first.Topic);
+        Assert.Equal("Werkstoffprüfung", second.Topic);
+        Assert.Equal(lesson.Id, second.Lesson?.Id);
+    }
+
     [Fact]
     public void Load_KeineAnstehendenFerien_KeinBadge()
     {
@@ -1177,3 +1302,43 @@ public sealed class TimetableViewModelTests
         Assert.False(vm.HasUntisMismatch);
     }
 }
+
+/// Nutzer-Feedback (zweite Runde): das Popup-Menü je Wochenraster-Kachel (TimetableView.axaml,
+/// MenuFlyout) blendet "Unterrichtsansicht"/"Planungsviewer" per IsVisible="{Binding HasLesson}"
+/// aus, wenn für den Slot noch keine Lesson existiert, und den ganzen Menü-Trigger per
+/// IsVisible="{Binding HasGroupId}", wenn die Kachel gar keiner Gruppe zugeordnet ist (z.B. eine
+/// GroupId-lose Vertretung). Diese beiden Properties sind die Grundlage dafür.
+public sealed class WeekCellItemMenuVisibilityTests
+{
+    [Fact]
+    public void ForSlot_MitLesson_HatHasLessonUndHasGroupId()
+    {
+        var lesson = new Lesson { Topic = "Redox" };
+        var cell = WeekCellItem.ForSlot(DayOfWeek.Monday, 3, isToday: true, "Che", "Q1 Chemie",
+            "R204", "Redox", "#4C8DFF", "", hasExam: false, isLastBeforeExam: false,
+            hasExperiment: false, Guid.NewGuid(), isHoliday: false, lesson: lesson);
+
+        Assert.True(cell.HasLesson);
+        Assert.True(cell.HasGroupId);
+    }
+
+    [Fact]
+    public void ForSlot_OhneLesson_HatKeinHasLesson()
+    {
+        var cell = WeekCellItem.ForSlot(DayOfWeek.Monday, 3, isToday: true, "Che", "Q1 Chemie",
+            "R204", "", "#4C8DFF", "", hasExam: false, isLastBeforeExam: false,
+            hasExperiment: false, Guid.NewGuid(), isHoliday: false);
+
+        Assert.False(cell.HasLesson);
+        Assert.True(cell.HasGroupId);
+    }
+
+    [Fact]
+    public void ForSubstitutionLesson_OhneGroupId_HatKeinHasGroupId()
+    {
+        var cell = WeekCellItem.ForSubstitutionLesson(DayOfWeek.Monday, 3, isToday: true,
+            new SubstitutionEntry { GroupId = null, GroupLabel = "Fremde Klasse", Description = "Vertretung" });
+
+        Assert.False(cell.HasGroupId);
+    }
+}

LehrerApp.Desktop.Tests/UntisNameMatchingTests.cs

@@ -0,0 +1,21 @@
+using LehrerApp.Desktop.ViewModels.ClassTeacher;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class UntisNameMatchingTests
+{
+    [Theory]
+    [InlineData("Ben Schmidt", "Schmidt Ben")]
+    [InlineData("Ada Müller", "MÜLLER ADA")]
+    [InlineData("Max Mustermann", "mustermann   max")]
+    public void NamesMatch_IstReihenfolgeUndGrossKleinschreibungUnabhaengig(string a, string b) =>
+        Assert.True(UntisNameMatching.NamesMatch(a, b));
+
+    [Theory]
+    [InlineData("Ben Schmidt", "Ben Müller")]
+    [InlineData(null, "Ben Schmidt")]
+    [InlineData("Ben Schmidt", "")]
+    public void NamesMatch_LehntUnterschiedlicheOderFehlendeNamenAb(string? a, string b) =>
+        Assert.False(UntisNameMatching.NamesMatch(a, b));
+}

LehrerApp.Desktop.Tests/UntisReportCacheServiceTests.cs

@@ -0,0 +1,208 @@
+using System.Net;
+using System.Text;
+using LehrerApp.Core.Models;
+using LehrerApp.Desktop.Services;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class UntisReportCacheServiceTests
+{
+    private static readonly DateOnly Today = new(2026, 8, 25);
+    private static readonly DateOnly HotStart = Today.AddDays(-14);
+
+    // ── Plan(): reine Entscheidungslogik, keine Repositories/HTTP nötig ──────────
+
+    [Fact]
+    public void Plan_ErsterAufruf_LaedtHeissesFensterUndDeckungReichtBisFensteranfang()
+    {
+        var plan = UntisReportCacheService.Plan(null, Today, Today, Today, forceRefresh: false, DateTime.UtcNow);
+
+        Assert.True(plan.RefreshHotWindow);
+        Assert.Equal(HotStart, plan.HotWindowStart);
+        Assert.Equal(Today, plan.HotWindowEnd);
+        Assert.False(plan.FetchColdRange);
+        Assert.Equal(Int(HotStart), plan.ResultingColdCoverageStartDate);
+    }
+
+    [Fact]
+    public void Plan_InnerhalbEinerStunde_KeinErneutesHeissesFenster()
+    {
+        var state = new UntisCacheFetchState
+        {
+            ClassName = "10c", Kind = UntisCacheKind.Absences,
+            HotWindowFetchedAt = DateTime.UtcNow.AddMinutes(-10), ColdCoverageStartDate = Int(HotStart),
+        };
+
+        var plan = UntisReportCacheService.Plan(state, Today, Today, Today, forceRefresh: false, DateTime.UtcNow);
+
+        Assert.False(plan.RefreshHotWindow);
+        Assert.False(plan.FetchColdRange);
+    }
+
+    [Fact]
+    public void Plan_ForceRefresh_LoestTrotzKuerzlichemAbrufAus()
+    {
+        var state = new UntisCacheFetchState
+        {
+            ClassName = "10c", Kind = UntisCacheKind.Absences,
+            HotWindowFetchedAt = DateTime.UtcNow.AddMinutes(-10), ColdCoverageStartDate = Int(HotStart),
+        };
+
+        var plan = UntisReportCacheService.Plan(state, Today, Today, Today, forceRefresh: true, DateTime.UtcNow);
+
+        Assert.True(plan.RefreshHotWindow);
+    }
+
+    [Fact]
+    public void Plan_MehrAlsEineStundeVergangen_FrischtHeissesFensterErneutAuf()
+    {
+        var state = new UntisCacheFetchState
+        {
+            ClassName = "10c", Kind = UntisCacheKind.Absences,
+            HotWindowFetchedAt = DateTime.UtcNow.AddHours(-2), ColdCoverageStartDate = Int(HotStart),
+        };
+
+        var plan = UntisReportCacheService.Plan(state, Today, Today, Today, forceRefresh: false, DateTime.UtcNow);
+
+        Assert.True(plan.RefreshHotWindow);
+    }
+
+    [Fact]
+    public void Plan_AnfrageVorDemHeissenFenster_KeinHeissesFensterAberKalterErstabruf()
+    {
+        var requestStart = HotStart.AddDays(-30);
+        var requestEnd = HotStart.AddDays(-5);
+
+        var plan = UntisReportCacheService.Plan(null, requestStart, requestEnd, Today, forceRefresh: false, DateTime.UtcNow);
+
+        Assert.False(plan.RefreshHotWindow);
+        Assert.True(plan.FetchColdRange);
+        Assert.Equal(requestStart, plan.ColdRangeStart);
+        Assert.Equal(HotStart.AddDays(-1), plan.ColdRangeEnd);
+        Assert.Equal(Int(requestStart), plan.ResultingColdCoverageStartDate);
+    }
+
+    [Fact]
+    public void Plan_BereitsKaltAbgedeckterBereich_KeinAbrufNoetig()
+    {
+        var coveredSince = HotStart.AddDays(-60);
+        var state = new UntisCacheFetchState
+        {
+            ClassName = "10c", Kind = UntisCacheKind.Absences,
+            HotWindowFetchedAt = DateTime.UtcNow, ColdCoverageStartDate = Int(coveredSince),
+        };
+
+        var plan = UntisReportCacheService.Plan(state, coveredSince.AddDays(10), HotStart.AddDays(-20),
+            Today, forceRefresh: false, DateTime.UtcNow);
+
+        Assert.False(plan.RefreshHotWindow);
+        Assert.False(plan.FetchColdRange);
+    }
+
+    [Fact]
+    public void Plan_ErweitertKalteAbdeckungNurBisZumBenoetigtenStart()
+    {
+        var coveredSince = HotStart.AddDays(-30);
+        var earlierStart = HotStart.AddDays(-90);
+        var state = new UntisCacheFetchState
+        {
+            ClassName = "10c", Kind = UntisCacheKind.Absences,
+            HotWindowFetchedAt = DateTime.UtcNow, ColdCoverageStartDate = Int(coveredSince),
+        };
+
+        var plan = UntisReportCacheService.Plan(state, earlierStart, HotStart.AddDays(-40),
+            Today, forceRefresh: false, DateTime.UtcNow);
+
+        Assert.False(plan.RefreshHotWindow);
+        Assert.True(plan.FetchColdRange);
+        Assert.Equal(earlierStart, plan.ColdRangeStart);
+        Assert.Equal(coveredSince.AddDays(-1), plan.ColdRangeEnd);
+        Assert.Equal(Int(earlierStart), plan.ResultingColdCoverageStartDate);
+    }
+
+    private static int Int(DateOnly date) => date.Year * 10000 + date.Month * 100 + date.Day;
+
+    // ── Ende-zu-Ende: erster Aufruf ruft WebUntis ab, zweiter Aufruf binnen einer Stunde nicht ──
+
+    [Fact]
+    public async Task GetClassRegisterEventsAsync_ZweiterAufrufBinnenEinerStunde_RuftWebUntisNichtErneutAb()
+    {
+        var todayLabel = DateTime.Today.ToString("dd.MM.yy");
+        var csv = Encoding.UTF8.GetBytes(
+            "Klasse\tDatum\tFach\tName\tBenutzer\tEintragskategorie\tKategoriegruppe\tText\r\n" +
+            $"10c\t{todayLabel}\tNAT\tMuster Max\tmueller\tMitarb. über Erwart.\tPositiv\tArbeitet gut mit.\r\n");
+        var handler = new QueueHandler(
+            Json("{\"result\":{\"sessionId\":\"s\"}}"),
+            Json("{\"result\":[{\"id\":1,\"name\":\"2026/27\",\"startDate\":20260801,\"endDate\":20270731}]}"),
+            Json("{\"data\":{\"finished\":true,\"error\":false," +
+                 "\"reportParams\":\"get=rpt.tmp&name=ClassregEventPerStudent&format=csv\"}}"),
+            new HttpResponseMessage(HttpStatusCode.OK) { Content = new ByteArrayContent(csv) });
+        var settings = TestSupport.BuildWebUntisSettingsService();
+        await using var untis = new WebUntisIntegrationService(new HttpClient(handler), settings);
+        await untis.ConnectAsync(new WebUntisCredentials("bk-ostvest", "arche.webuntis.com", "lehrkraft", "geheim"));
+
+        var absenceCache = new FakeUntisAbsenceCache();
+        var classRegisterCache = new FakeUntisClassRegisterCache();
+        var rosterCache = new FakeUntisStudentRosterCache();
+        var fetchStates = new FakeUntisCacheFetchStates();
+        var cache = new UntisReportCacheService(untis, absenceCache, classRegisterCache, rosterCache, fetchStates);
+        var today = DateOnly.FromDateTime(DateTime.Today);
+
+        var first = await cache.GetClassRegisterEventsAsync("10c", today, today);
+        Assert.Single(first);
+        Assert.Equal(4, handler.Requests.Count);
+
+        var second = await cache.GetClassRegisterEventsAsync("10c", today, today);
+        Assert.Single(second);
+        Assert.Equal(4, handler.Requests.Count); // keine weiteren Anfragen - aus dem Cache bedient
+    }
+
+    [Fact]
+    public async Task GetStudentRosterAsync_ZweiterAufrufBinnenEinerStunde_RuftWebUntisNichtErneutAb()
+    {
+        var csv = Encoding.UTF8.GetBytes(
+            "id\texternKey\tklasse.name\tname\tlongName\tforeName\r\n" +
+            "1\t9001\t10c\tMUST\tMustermann\tMax\r\n");
+        var handler = new QueueHandler(
+            Json("{\"result\":{\"sessionId\":\"s\"}}"),
+            Json("{\"result\":[{\"id\":1,\"name\":\"2026/27\",\"startDate\":20260801,\"endDate\":20270731}]}"),
+            Json("{\"data\":{\"finished\":true,\"error\":false," +
+                 "\"reportParams\":\"get=rpt.tmp&name=Student&format=csv\"}}"),
+            new HttpResponseMessage(HttpStatusCode.OK) { Content = new ByteArrayContent(csv) });
+        var settings = TestSupport.BuildWebUntisSettingsService();
+        await using var untis = new WebUntisIntegrationService(new HttpClient(handler), settings);
+        await untis.ConnectAsync(new WebUntisCredentials("bk-ostvest", "arche.webuntis.com", "lehrkraft", "geheim"));
+
+        var cache = new UntisReportCacheService(untis, new FakeUntisAbsenceCache(), new FakeUntisClassRegisterCache(),
+            new FakeUntisStudentRosterCache(), new FakeUntisCacheFetchStates());
+
+        var first = await cache.GetStudentRosterAsync("10c");
+        Assert.Single(first);
+        Assert.Equal("Max Mustermann", first[0].DisplayName);
+        Assert.Equal(4, handler.Requests.Count);
+
+        var second = await cache.GetStudentRosterAsync("10c");
+        Assert.Single(second);
+        Assert.Equal(4, handler.Requests.Count); // keine weiteren Anfragen - aus dem Cache bedient
+    }
+
+    private static HttpResponseMessage Json(string json) => new(HttpStatusCode.OK)
+    {
+        Content = new StringContent(json, Encoding.UTF8, "application/json"),
+    };
+
+    private sealed class QueueHandler(params HttpResponseMessage[] responses) : HttpMessageHandler
+    {
+        private readonly Queue<HttpResponseMessage> _responses = new(responses);
+        public List<string> Requests { get; } = [];
+
+        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
+            CancellationToken cancellationToken)
+        {
+            Requests.Add(request.RequestUri?.ToString() ?? "");
+            await Task.Yield();
+            return _responses.Dequeue();
+        }
+    }
+}

LehrerApp.Desktop.Tests/WebUntisIntegrationServiceTests.cs

@@ -0,0 +1,88 @@
+using System.Net;
+using System.Text;
+using LehrerApp.Desktop.Services;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class WebUntisIntegrationServiceTests
+{
+    [Fact]
+    public async Task ConnectUndAbruf_GehenDirektAnWebUntisUndVerwendenDieselbeSession()
+    {
+        var handler = new QueueHandler(
+            Json("{\"result\":{\"sessionId\":\"desktop-session\"}}"),
+            Json("{\"result\":[{\"id\":1,\"name\":\"2026/27\",\"startDate\":20260801,\"endDate\":20270731}]}"),
+            Json("{\"result\":[{\"id\":42,\"name\":\"KUE\",\"longName\":\"Kürbis\",\"active\":true}]}"),
+            Json("{\"result\":{}}"));
+        var settings = TestSupport.BuildWebUntisSettingsService();
+        await using var service = new WebUntisIntegrationService(new HttpClient(handler), settings);
+
+        await service.ConnectAsync(new WebUntisCredentials(
+            "bk-ostvest", "arche.webuntis.com", "lehrkraft", "geheim"));
+        var teachers = await service.GetTeachersAsync();
+
+        Assert.Equal("KUE", Assert.Single(teachers).Name);
+        Assert.Equal(3, handler.Requests.Count);
+        Assert.All(handler.Requests, request =>
+            Assert.StartsWith("https://arche.webuntis.com/WebUntis/", request.Uri));
+        Assert.DoesNotContain(handler.Requests, request => request.Uri.Contains("/api/webuntis"));
+        Assert.Single(handler.Requests, request => request.Body.Contains("\"method\":\"authenticate\""));
+    }
+
+    [Fact]
+    public async Task GetClassAbsencesAsync_LoestKlasseNamensbasiertAufUndAdressiertSieAlsKLPlusId()
+    {
+        var csv = Encoding.UTF8.GetBytes(
+            "Schüler*innen\tExterne Id\tText\tKlasse\tDatum\tWochentag\tFehlstd.\tFehlmin.\tLehrkraft\tFach\t" +
+            "Abwesenheitsgrund\tText\tENr\tErledigt\tAbwesenheit zählt\tEntschuldigungstext\tStundennr.\tStatus\tFehltage\r\n" +
+            "Muster Max\t12345\t\t10c\t24.08.26\tMo.\t1\t45\tHED\tChe\tAbsent\tKrank gemeldet\t555\t24.08.26\ttrue\t\t3\tnicht entsch.\t1\r\n");
+        var handler = new QueueHandler(
+            Json("{\"result\":{\"sessionId\":\"desktop-session\"}}"), // authenticate (ConnectAsync)
+            Json("{\"result\":[{\"id\":7,\"name\":\"2026/27\",\"startDate\":20260801,\"endDate\":20270731}]}"), // getSchoolyears (ConnectAsync-Validierung)
+            Json("{\"result\":[{\"id\":7,\"name\":\"2026/27\",\"startDate\":20260801,\"endDate\":20270731}]}"), // getSchoolyears (ResolveClassIdAsync)
+            Json("{\"result\":[{\"id\":874,\"name\":\"10c\"}]}"), // getKlassen
+            Json("{\"data\":{\"finished\":true,\"error\":false," +
+                 "\"reportParams\":\"get=rpt.tmp&name=AbsencePerStudent&format=csv\"}}"),
+            new HttpResponseMessage(HttpStatusCode.OK) { Content = new ByteArrayContent(csv) },
+            Json("{\"result\":{}}")); // logout (Dispose)
+        var settings = TestSupport.BuildWebUntisSettingsService();
+        await using var service = new WebUntisIntegrationService(new HttpClient(handler), settings);
+
+        await service.ConnectAsync(new WebUntisCredentials(
+            "bk-ostvest", "arche.webuntis.com", "lehrkraft", "geheim"));
+        var entries = await service.GetClassAbsencesAsync("10c",
+            new DateOnly(2026, 8, 24), new DateOnly(2026, 8, 28));
+
+        var entry = Assert.Single(entries);
+        Assert.Equal("Muster Max", entry.StudentName);
+        Assert.Equal("nicht entsch.", entry.Status);
+        // Zweimal getSchoolyears: einmal als ConnectAsync-Validierung, einmal in ResolveClassIdAsync.
+        Assert.Equal(2, handler.Requests.Count(request => request.Body.Contains("\"method\":\"getSchoolyears\"")));
+        Assert.Single(handler.Requests, request => request.Body.Contains("\"method\":\"getKlassen\""));
+        Assert.Single(handler.Requests, request =>
+            request.Uri.Contains("reports.do?name=AbsencePerStudent") &&
+            request.Uri.Contains("klasseOrStudentgroupId=KL874"));
+    }
+
+    private static HttpResponseMessage Json(string json) => new(HttpStatusCode.OK)
+    {
+        Content = new StringContent(json, Encoding.UTF8, "application/json"),
+    };
+
+    private sealed class QueueHandler(params HttpResponseMessage[] responses) : HttpMessageHandler
+    {
+        private readonly Queue<HttpResponseMessage> _responses = new(responses);
+        public List<CapturedRequest> Requests { get; } = [];
+
+        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
+            CancellationToken cancellationToken)
+        {
+            Requests.Add(new(request.RequestUri?.ToString() ?? "",
+                request.Content is null ? "" : await request.Content.ReadAsStringAsync(cancellationToken)));
+            return _responses.Dequeue();
+        }
+    }
+
+    private sealed record CapturedRequest(string Uri, string Body);
+}

LehrerApp.Desktop.Tests/WebUntisSettingsServiceTests.cs

@@ -86,4 +86,39 @@ public sealed class WebUntisSettingsServiceTests
         Assert.Equal(at, reloaded.LastSyncAt);
         Assert.Equal("3 Vertretungen erkannt", reloaded.LastSyncStatus);
     }
+
+    [Fact]
+    public void ApiCredentials_SindVerschluesseltUndPersistieren()
+    {
+        var path = BuildTempPath();
+        var credentials = new WebUntisCredentials("schule", "mese.webuntis.com", "lehrkraft", "sehr geheim");
+        var service = new WebUntisSettingsService(path);
+
+        service.SetApiCredentials(credentials);
+        service.SetTeacherUntisId(4711);
+
+        var raw = File.ReadAllText(Path.Combine(path, "webuntis-settings.json"));
+        var reloaded = new WebUntisSettingsService(path);
+        Assert.DoesNotContain("sehr geheim", raw);
+        Assert.True(reloaded.ApiIsConfigured);
+        Assert.Equal(credentials, reloaded.GetApiCredentials());
+        Assert.Equal(4711, reloaded.TeacherUntisId);
+    }
+
+    [Fact]
+    public void ClearApiCredentials_LaesstIcalKonfigurationUnveraendert()
+    {
+        var service = new WebUntisSettingsService(BuildTempPath());
+        service.SetIcalUrl(SampleUrl);
+        service.SetApiCredentials(new("schule", "", "user", "password"));
+        service.SetTeacherUntisId(12);
+
+        service.ClearApiCredentials();
+
+        Assert.False(service.ApiIsConfigured);
+        Assert.Null(service.GetApiCredentials());
+        Assert.Null(service.TeacherUntisId);
+        Assert.True(service.IsConfigured);
+        Assert.Equal(SampleUrl, service.GetIcalUrl());
+    }
 }

LehrerApp.Desktop/App.axaml

@@ -2,6 +2,25 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="LehrerApp.Desktop.App"
              RequestedThemeVariant="Default">
+  <Application.Resources>
+    <ResourceDictionary>
+      <ResourceDictionary.MergedDictionaries>
+        <ResourceInclude Source="avares://LehrerApp.Desktop/Styles/SemanticBrushes.axaml"/>
+      </ResourceDictionary.MergedDictionaries>
+      <!-- Plattformunabhängige Vektoricons für die Hauptnavigation (14.10). -->
+      <StreamGeometry x:Key="IconSearch">M10,2 A8,8 0 1 0 10,18 A8,8 0 1 0 10,2 M10,5 A5,5 0 1 1 10,15 A5,5 0 1 1 10,5 M15,14 L22,21 L20,23 L13,16 Z</StreamGeometry>
+      <StreamGeometry x:Key="IconDashboard">M3,3 H10 V10 H3 Z M14,3 H21 V7 H14 Z M14,11 H21 V21 H14 Z M3,14 H10 V21 H3 Z</StreamGeometry>
+      <StreamGeometry x:Key="IconGroups">M3,8 L12,3 L21,8 V10 H3 Z M5,11 H8 V18 H5 Z M10,11 H14 V18 H10 Z M16,11 H19 V18 H16 Z M3,20 H21 V22 H3 Z</StreamGeometry>
+      <StreamGeometry x:Key="IconStudents">M12,3 A4,4 0 1 0 12,11 A4,4 0 1 0 12,3 M4,21 C4,16 7,13 12,13 C17,13 20,16 20,21 Z</StreamGeometry>
+      <StreamGeometry x:Key="IconExams">M5,2 H15 L20,7 V22 H5 Z M7,5 V19 H18 V9 H13 V4 H7 Z M9,11 H16 V13 H9 Z M9,15 H16 V17 H9 Z</StreamGeometry>
+      <StreamGeometry x:Key="IconCalendar">M3,4 H21 V22 H3 Z M5,10 V20 H19 V10 Z M7,2 H9 V7 H7 Z M15,2 H17 V7 H15 Z M7,12 H10 V15 H7 Z M12,12 H15 V15 H12 Z M7,17 H10 V19 H7 Z M12,17 H15 V19 H12 Z</StreamGeometry>
+      <StreamGeometry x:Key="IconClock">M12,2 A10,10 0 1 0 12,22 A10,10 0 1 0 12,2 M12,5 A7,7 0 1 1 12,19 A7,7 0 1 1 12,5 M11,7 H13 V12 L17,14 L16,16 L11,13 Z</StreamGeometry>
+      <StreamGeometry x:Key="IconClassTeacher">M2,8 L12,3 L22,8 L12,13 Z M6,11 V16 C9,19 15,19 18,16 V11 M22,8 V15</StreamGeometry>
+      <StreamGeometry x:Key="IconSettings">M3,5 H21 V7 H3 Z M8,3 A3,3 0 1 0 8,9 A3,3 0 1 0 8,3 M3,11 H21 V13 H3 Z M16,9 A3,3 0 1 0 16,15 A3,3 0 1 0 16,9 M3,17 H21 V19 H3 Z M10,15 A3,3 0 1 0 10,21 A3,3 0 1 0 10,15</StreamGeometry>
+      <StreamGeometry x:Key="IconRefresh">M12,3 A9,9 0 0 1 21,12 H18 A6,6 0 0 0 8,7 L11,10 H3 V2 L6,5 A9,9 0 0 1 12,3 M12,21 A9,9 0 0 1 3,12 H6 A6,6 0 0 0 16,17 L13,14 H21 V22 L18,19 A9,9 0 0 1 12,21</StreamGeometry>
+    </ResourceDictionary>
+  </Application.Resources>
+
   <Application.Styles>
     <FluentTheme />
     <StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Fluent.xaml"/>
@@ -16,5 +35,17 @@
       <Setter Property="Opacity" Value="0.4"/>
       <Setter Property="FontSize" Value="13"/>
     </Style>
+    <Style Selector="Button.touchTarget">
+      <Setter Property="MinWidth" Value="40"/>
+      <Setter Property="MinHeight" Value="40"/>
+    </Style>
+    <Style Selector="Button:focus-visible">
+      <Setter Property="BorderBrush" Value="{DynamicResource SystemAccentColor}"/>
+      <Setter Property="BorderThickness" Value="2"/>
+    </Style>
+    <Style Selector="TextBox:focus-visible, ComboBox:focus-visible">
+      <Setter Property="BorderBrush" Value="{DynamicResource SystemAccentColor}"/>
+      <Setter Property="BorderThickness" Value="2"/>
+    </Style>
   </Application.Styles>
 </Application>

LehrerApp.Desktop/App.axaml.cs

@@ -3,6 +3,7 @@ using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Markup.Xaml;
 using Avalonia.Styling;
 using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
 using LehrerApp.Core.Services;
 using LehrerApp.Data;
 using LehrerApp.Desktop.Services;
@@ -10,7 +11,9 @@ using LehrerApp.Desktop.ViewModels;
 using LehrerApp.Desktop.ViewModels.Groups;
 using LehrerApp.Desktop.ViewModels.Planning;
 using LehrerApp.Desktop.ViewModels.Students;
+using LehrerApp.Desktop.ViewModels.Workload;
 using LehrerApp.Desktop.Views;
+using LehrerApp.Desktop.Views.Workload;
 using LehrerApp.Sync;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -79,6 +82,15 @@ public class App : Application
 
         var mainVm = Services.GetRequiredService<MainWindowViewModel>();
         WireCallbacks(mainVm);
+
+        // DI-Singletons werden erst beim ersten Auflösen erzeugt. Ohne dieses explizite
+        // Auflösen entstand der Timer des optionalen WebUntis-Abgleichs erst, wenn die
+        // Einstellungen geöffnet oder ein manueller Abruf gestartet wurde. Den Dienst beim
+        // Anwendungsstart aktivieren und wie den Jahresplan sofort einmal abgleichen; danach
+        // übernimmt sein stündlicher Timer.
+        if (Services.GetService<UntisSyncService>() is { } untisSync)
+            _ = untisSync.PollAsync();
+
         var main = new MainWindow { DataContext = mainVm };
         main.EnableWindowSizePersistence(Services.GetRequiredService<WindowSettingsService>());
         if (Services.GetService<SyncEngine>() is { } syncEngine)
@@ -100,11 +112,12 @@ public class App : Application
 
     private static void DisposeServices()
     {
-        if (_serviceProvider is null) return;
+        var serviceProvider = Interlocked.Exchange(ref _serviceProvider, null);
+        if (serviceProvider is null) return;
 
         try
         {
-            _serviceProvider.GetService<LiteDbContext>()?.Checkpoint();
+            serviceProvider.GetService<LiteDbContext>()?.Checkpoint();
         }
         catch (Exception ex)
         {
@@ -112,8 +125,19 @@ public class App : Application
         }
         finally
         {
-            _serviceProvider.Dispose();
+            // Der Exit-Handler läuft synchron auf dem Avalonia-UI-Thread. Die asynchrone
-            _serviceProvider = null;
+            // Entsorgung darf dort nicht mit GetResult() gestartet werden: Fortsetzungen aus
+            // WebUntis/HttpClient könnten sonst auf den blockierten UI-Kontext zurückwarten.
+            try
+            {
+                Task.Run(async () =>
+                    await serviceProvider.DisposeAsync().ConfigureAwait(false))
+                    .GetAwaiter().GetResult();
+            }
+            catch (Exception ex)
+            {
+                AppBootstrapper.Logger.Error("Dienste konnten beim Beenden nicht vollständig freigegeben werden.", ex);
+            }
         }
     }
 
@@ -130,6 +154,28 @@ public class App : Application
         dash.OnNavigateToLesson  = id => main.NavigateToGroupDetail(id, 3); // Tab "Mitarbeit"
         dash.OnNavigateToExam    = id => main.NavigateToGroupDetail(id, 4); // Tab "Klausuren"
         dash.OnNavigateToUnplannedLesson = id => main.NavigateToGroupDetail(id, 6); // Tab "Planung"
+        dash.OnAddMissingTeachingTime = item => ShowMissingTeachingTimeDialog(item, dash);
+
+        var examsOverview = Services.GetRequiredService<ViewModels.Exams.ExamsOverviewViewModel>();
+        examsOverview.OnNavigateToGroups = () => main.NavigateToCommand.Execute(NavItem.Groups);
+
+        // Globale Suche/Schnellerfassung (14.2): Navigation bleibt im MainWindow-VM, die
+        // vorhandenen Dialog-Helfer übernehmen Eingabe und Validierung.
+        var search = Services.GetRequiredService<GlobalSearchViewModel>();
+        search.OnNavigate = result =>
+        {
+            if (result.Kind == GlobalSearchResultKind.Student && result.EntityId is { } studentId)
+                main.NavigateToStudent(studentId);
+            else if (result.Kind == GlobalSearchResultKind.Group && result.GroupId is { } groupId)
+                main.NavigateToGroupDetail(groupId);
+            else if (result.Kind == GlobalSearchResultKind.Exam && result.GroupId is { } examGroupId)
+                main.NavigateToGroupDetail(examGroupId, 4);
+            else if (result.Kind == GlobalSearchResultKind.Task)
+                main.NavigateToWorkload();
+        };
+        search.OnQuickAddTask = startAsReminder => ShowQuickTaskDialog(startAsReminder, dash);
+        search.OnQuickAddStudent = ShowAddStudentDialog;
+        search.OnQuickAddGroupDocumentation = () => ShowQuickGroupDocumentationDialog(dash);
 
         // StudentList → StudentDetail + Anlegen
         var sl = Services.GetRequiredService<StudentListViewModel>();
@@ -150,4 +196,62 @@ public class App : Application
         if (Application.Current?.ApplicationLifetime is IClassicDesktopStyleApplicationLifetime { MainWindow: { } owner })
             await dialog.ShowDialog<bool>(owner);
     }
+
+    private static async Task ShowQuickTaskDialog(bool startAsReminder, DashboardViewModel dashboard)
+    {
+        if (Application.Current?.ApplicationLifetime is not IClassicDesktopStyleApplicationLifetime
+            { MainWindow: { } owner }) return;
+
+        var result = await WorkTaskDialogHelper.ShowDialog(owner, startAsReminder: startAsReminder);
+        if (result is null) return;
+
+        Services.GetRequiredService<IWorkTaskRepository>().Save(result);
+        dashboard.RefreshCommand.Execute(null);
+        Services.GetRequiredService<WorkTaskListViewModel>().Load();
+    }
+
+    private static async Task ShowMissingTeachingTimeDialog(MissingTeachingTimeItem item, DashboardViewModel dashboard)
+    {
+        if (Application.Current?.ApplicationLifetime is not IClassicDesktopStyleApplicationLifetime
+            { MainWindow: { } owner }) return;
+
+        var tasks = Services.GetRequiredService<IWorkTaskRepository>()
+            .GetAll().Where(t => t.Status != WorkTaskStatus.Done).ToList();
+        var vm = new AddTimeEntryDialogViewModel(tasks)
+        {
+            DateText = item.Date.ToString("dd.MM.yyyy"),
+            SelectedCategory = "Unterricht",
+            StartTimeText = item.WindowStart.ToString("HH:mm"),
+            EndTimeText = item.WindowEnd.ToString("HH:mm"),
+        };
+        var dialog = new AddTimeEntryDialog { DataContext = vm };
+        await dialog.ShowDialog<bool>(owner);
+        if (vm.Result is null) return;
+
+        Services.GetRequiredService<ITimeEntryRepository>().Save(vm.Result);
+        dashboard.RefreshCommand.Execute(null);
+        Services.GetRequiredService<TimeTrackingViewModel>().Load();
+    }
+
+    private static async Task ShowQuickGroupDocumentationDialog(DashboardViewModel dashboard)
+    {
+        if (Application.Current?.ApplicationLifetime is not IClassicDesktopStyleApplicationLifetime
+            { MainWindow: { } owner }) return;
+
+        var subjects = Services.GetRequiredService<ISubjectRepository>().GetAll()
+            .ToDictionary(s => s.Id);
+        var options = Services.GetRequiredService<IGroupRepository>().GetAll()
+            .Where(g => g.IsActive)
+            .OrderBy(g => g.Name)
+            .Select(g => new GroupDocumentationOption(g.Id,
+                g.SubjectId is { } subjectId && subjects.TryGetValue(subjectId, out var subject)
+                    ? $"{g.Name} · {(string.IsNullOrWhiteSpace(subject.ShortName) ? subject.Name : subject.ShortName)}"
+                    : g.Name));
+        var vm = new GroupDocumentationQuickViewModel(options);
+        var dialog = new Views.Students.GroupDocumentationQuickDialog { DataContext = vm };
+        if (!await dialog.ShowDialog<bool>(owner) || vm.Result is null) return;
+
+        Services.GetRequiredService<IDocumentationRepository>().Save(vm.Result);
+        dashboard.RefreshCommand.Execute(null);
+    }
 }

LehrerApp.Desktop/AppBootstrapper.cs

@@ -5,6 +5,8 @@ using LehrerApp.Data;
 using LehrerApp.Data.Repositories;
 using LehrerApp.Desktop.Services;
 using LehrerApp.Desktop.ViewModels;
+using LehrerApp.Desktop.ViewModels.ClassTeacher;
+using LehrerApp.Desktop.ViewModels.Exams;
 using LehrerApp.Desktop.ViewModels.Groups;
 using LehrerApp.Desktop.ViewModels.Planning;
 using LehrerApp.Desktop.ViewModels.Settings;
@@ -14,6 +16,7 @@ using LehrerApp.Sync;
 using LehrerApp.Sync.Crypto;
 using LehrerApp.Sync.Models;
 using Microsoft.Extensions.DependencyInjection;
+using LehrerApp.Templating;
 
 namespace LehrerApp.Desktop;
 
@@ -115,13 +118,22 @@ public static class AppBootstrapper
         services.AddSingleton<NotificationService>();
         services.AddSingleton<ExportService>();
         services.AddSingleton<PdfExportService>();
+        services.AddSingleton<ITemplateLoader, TemplateLoader>();
+        services.AddSingleton<ITemplateRenderer, QuestTemplateRenderer>();
+        services.AddSingleton(_ => new TemplateStore(appData));
 
         // ── Datensicherheit (13.3) ───────────────────────────────────────────
         // Backup läuft vor dem Öffnen der Datenbank, rein dateibasiert (unabhängig von
         // Verschlüsselung) — reine Datei-Kopie, kein offener LiteDB-Handle nötig.
-        var backup = new BackupService(appData);
+        var backupSettings = new BackupSettingsService(appData);
-        backup.CreateBackup(DbPath);
+        var backup = new BackupService(appData) { SecondaryBackupDirectory = backupSettings.LoadSecondaryDirectory() };
+        var backupPath = backup.CreateBackup(DbPath);
+        // Best-effort-Prüfung des automatischen Startbackups: nur geloggt, kein Blocker für den
+        // Programmstart — ein beschädigtes Backup soll auffallen, nicht den Nutzer aufhalten.
+        if (backupPath is not null && !new DatabaseEncryptionService().CanOpenAndRead(backupPath, DbPassword))
+            Logger.Warn($"Automatisches Backup {backupPath} lässt sich nicht öffnen/lesen — möglicherweise beschädigt.");
         services.AddSingleton(backup);
+        services.AddSingleton(backupSettings);
         services.AddSingleton(_ => new AppLockService(appData));
         services.AddSingleton<DatabaseEncryptionService>();
         services.AddSingleton(_ => new PrivacySettingsService(appData));
@@ -168,6 +180,10 @@ public static class AppBootstrapper
         services.AddSingleton<IUntisSnapshotRepository, UntisSnapshotRepository>();
         services.AddSingleton<IUntisSlotMappingRepository, UntisSlotMappingRepository>();
         services.AddSingleton<IAnnualPlanEventRepository, AnnualPlanEventRepository>();
+        services.AddSingleton<IUntisAbsenceCacheRepository, UntisAbsenceCacheRepository>();
+        services.AddSingleton<IUntisClassRegisterCacheRepository, UntisClassRegisterCacheRepository>();
+        services.AddSingleton<IUntisCacheFetchStateRepository, UntisCacheFetchStateRepository>();
+        services.AddSingleton<IUntisStudentRosterCacheRepository, UntisStudentRosterCacheRepository>();
 
         // ── Services ──────────────────────────────────────────────────────────
         services.AddSingleton<GradingService>();
@@ -181,7 +197,6 @@ public static class AppBootstrapper
         services.AddSingleton(_ => new DashboardSettingsService(appData));
         services.AddSingleton(_ => new WindowSettingsService(appData));
         services.AddSingleton(_ => new AppearanceSettingsService(appData));
-        services.AddSingleton(_ => new LetterTemplateService(appData));
         services.AddSingleton<PlanningExchangeService>();
 
         // ── KI-Unterstützung (4.5.9, optional – nur wenn in den Einstellungen aktiviert) ──────
@@ -223,6 +238,8 @@ public static class AppBootstrapper
         services.AddSingleton(syncSettings);
         services.AddSingleton(_ => new SyncAuthService(new HttpClient()));
         services.AddSingleton(sp => new SchoolWeatherService(new HttpClient(), syncSettings));
+        services.AddSingleton(sp => new WebUntisIntegrationService(new HttpClient(), untisSettings));
+        services.AddSingleton<UntisReportCacheService>();
         // War dieses Gerät schon eingeloggt, aber sync.key fehlt(e), wurde gerade eben (unten)
         // stillschweigend ein neuer, unabhängiger Schlüssel erzeugt - bisher unter dem ALTEN
         // Schlüssel synchronisierte Server-Daten sind für dieses Gerät dann nicht mehr lesbar.
@@ -284,6 +301,7 @@ public static class AppBootstrapper
         // Singleton: einmal erstellt, überall dieselbe Instanz
         services.AddSingleton<AppLockViewModel>();
         services.AddSingleton<MainWindowViewModel>();
+        services.AddSingleton<GlobalSearchViewModel>();
         services.AddSingleton<DashboardViewModel>();
         services.AddSingleton(sp =>
             new SyncStatusViewModel(
@@ -296,6 +314,9 @@ public static class AppBootstrapper
         services.AddSingleton<TimeTrackingViewModel>();
         services.AddSingleton<WorkloadEvaluationViewModel>();
         services.AddSingleton<WorkloadViewModel>();
+        services.AddSingleton<ClassTeacherDetailsViewModel>();
+        services.AddSingleton<ClassTeacherOverviewViewModel>();
+        services.AddSingleton<ExamsOverviewViewModel>();
 
         // Transient: neue Instanz pro Navigation (für Detailseiten)
         services.AddTransient<GroupDetailViewModel>();

LehrerApp.Desktop/Converters/FractionWidthConverter.cs

@@ -0,0 +1,24 @@
+using System.Collections.Generic;
+using System.Globalization;
+using Avalonia.Data.Converters;
+
+namespace LehrerApp.Desktop.Converters;
+
+/// <summary>Multipliziert die gerenderte Breite eines Referenzelements (typischerweise die neutrale
+/// Track-Leiste eines gestapelten Balkens) mit einem Anteil 0…1. Ersetzt eine im ViewModel hart
+/// codierte Pixelkonstante (Quick-Win, Nutzer-Feedback) — die Segmentbreite bleibt damit auch
+/// korrekt, wenn sich die Breite der Seitenspalte in XAML mal ändert, weil sie sich aus der
+/// tatsächlichen <c>Bounds.Width</c> des Track-Elements ergibt statt aus einer angenommenen
+/// festen Breite. `Grid.ColumnDefinitions` ließ sich dafür nicht binden (Avalonia bietet dort bei
+/// kompilierten Bindings keinen Setter — <c>AVLN3000</c>), deshalb MultiBinding auf Pixelbreite
+/// statt Grid-Sternspalten.</summary>
+public sealed class FractionWidthConverter : IMultiValueConverter
+{
+    public static readonly FractionWidthConverter Instance = new();
+
+    public object? Convert(IList<object?> values, Type targetType, object? parameter, CultureInfo culture)
+    {
+        if (values is not [double trackWidth, double fraction, ..] || double.IsNaN(trackWidth)) return 0d;
+        return Math.Max(0d, trackWidth * fraction);
+    }
+}

LehrerApp.Desktop/LehrerApp.Desktop.csproj

@@ -9,6 +9,8 @@
     <ProjectReference Include="..\LehrerApp.Core\LehrerApp.Core.csproj" />
     <ProjectReference Include="..\LehrerApp.Data\LehrerApp.Data.csproj" />
     <ProjectReference Include="..\LehrerApp.Sync\LehrerApp.Sync.csproj" />
+    <ProjectReference Include="..\LehrerApp.WebUntis\LehrerApp.WebUntis.csproj" />
+    <ProjectReference Include="..\LehrerApp.Templating\LehrerApp.Templating.csproj" />
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Avalonia" />

LehrerApp.Desktop/Services/BackupSettingsService.cs

@@ -0,0 +1,36 @@
+using System.Text.Json;
+
+namespace LehrerApp.Desktop.Services;
+
+internal sealed class BackupSettingsConfig
+{
+    public string? SecondaryDirectory { get; set; }
+}
+
+/// <summary>Merkt sich einen optionalen zweiten Sicherungsordner (13.3.1 Nachtrag) — z.B. ein
+/// USB-Stick oder Netzlaufwerk, damit ein Backup nicht ausschließlich neben der Live-Datenbank
+/// liegt und bei Plattenausfall oder gelöschtem Profilverzeichnis mit verloren geht. Gleiches
+/// Muster wie <see cref="AppearanceSettingsService"/>. Das eigentliche Kopieren übernimmt
+/// <see cref="LehrerApp.Core.Services.BackupService"/> bewusst best-effort.</summary>
+public sealed class BackupSettingsService
+{
+    private readonly string _configPath;
+
+    public BackupSettingsService(string appDataPath) =>
+        _configPath = Path.Combine(appDataPath, "backupsettings.json");
+
+    public string? LoadSecondaryDirectory()
+    {
+        try
+        {
+            if (File.Exists(_configPath))
+                return JsonSerializer.Deserialize<BackupSettingsConfig>(File.ReadAllText(_configPath))
+                       ?.SecondaryDirectory;
+        }
+        catch { /* beschädigte Konfiguration -> kein zweites Ziel */ }
+        return null;
+    }
+
+    public void SaveSecondaryDirectory(string? path) =>
+        File.WriteAllText(_configPath, JsonSerializer.Serialize(new BackupSettingsConfig { SecondaryDirectory = path }));
+}

LehrerApp.Desktop/Services/UntisReportCacheService.cs

@@ -0,0 +1,171 @@
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+
+namespace LehrerApp.Desktop.Services;
+
+/// <summary>Ergebnis von <see cref="UntisReportCacheService.Plan"/>: was für eine Anfrage
+/// [<c>RequestStart</c>..<c>RequestEnd</c>, nicht Teil dieses Records, siehe Aufrufer] tatsächlich
+/// live nachgeladen werden muss, und welcher Deckungsstand danach gilt. Bewusst als reine, ohne
+/// Repository/HTTP-Zugriff testbare Funktion ausgelagert (gleiches Muster wie
+/// <see cref="ClassTeacher.ClassAbsenceDaySummaryRow.GroupByStudentAndDay"/>).</summary>
+public readonly record struct UntisCacheRefreshPlan(
+    bool RefreshHotWindow, DateOnly HotWindowStart, DateOnly HotWindowEnd,
+    bool FetchColdRange, DateOnly ColdRangeStart, DateOnly ColdRangeEnd,
+    int? ResultingColdCoverageStartDate);
+
+/// <summary>
+/// Lokaler Cache für die beiden Klassenlehrer-Berichte (Fehlzeiten, Klassenbucheinträge anderer
+/// Lehrkräfte, siehe TODO.md) - Nutzer-Feedback: Warnungen sollen sofort da sein, ohne bei jedem
+/// Öffnen der Ansicht neu abzurufen, und der Bericht darf nicht mehrfach pro Stunde abgerufen
+/// werden (Sorge, bei WebUntis aufzufallen, wenn dieselbe Ansicht mehrfach geöffnet wird). Ein
+/// festes "heißes" Fenster der letzten <see cref="HotWindowDays"/> Tage wird höchstens stündlich
+/// aufgefrischt (dort kann sich der Status noch ändern, z. B. "ausstehend" → "entschuldigt");
+/// alles Ältere gilt als endgültig und wird, einmal abgerufen, dauerhaft aus dem Cache bedient.
+/// Die Cache-Tabellen selbst sind bewusst nicht synchronisiert (siehe
+/// <see cref="IUntisAbsenceCacheRepository"/>-Implementierung) - jedes Gerät füllt seinen Cache
+/// über diesen Service selbst.
+/// </summary>
+public sealed class UntisReportCacheService(
+    WebUntisIntegrationService untis,
+    IUntisAbsenceCacheRepository absenceCache,
+    IUntisClassRegisterCacheRepository classRegisterCache,
+    IUntisStudentRosterCacheRepository rosterCache,
+    IUntisCacheFetchStateRepository fetchState)
+{
+    private static readonly TimeSpan HotWindowRefreshInterval = TimeSpan.FromHours(1);
+    private const int HotWindowDays = 14;
+
+    /// Roster hat anders als Fehlzeiten/Klassenbuch keine Historie (nur "aktueller Stand einer
+    /// Klasse") - deshalb ohne heißes/kaltes Fenster, nur "gilt der letzte Abruf noch als frisch".
+    /// Behebt, dass die Klassenlehrer-Übersicht bei jedem Öffnen spürbar verzögert wirkte: der
+    /// Roster-Abruf lief bislang komplett am Cache vorbei live gegen WebUntis (Nutzer-Feedback).
+    public async Task<IReadOnlyList<UntisStudentRosterCacheEntry>> GetStudentRosterAsync(string className,
+        bool forceRefresh = false, CancellationToken token = default)
+    {
+        var state = fetchState.Get(className, UntisCacheKind.Roster);
+        if (NeedsRefresh(state, forceRefresh, DateTime.UtcNow))
+        {
+            var fresh = await untis.GetStudentsAsync(className, token);
+            rosterCache.ReplaceAll(className, fresh.Students.Select(s => new UntisStudentRosterCacheEntry
+            {
+                ClassName = className, ExternKey = s.ExternKey, DisplayName = s.DisplayName,
+            }));
+            fetchState.Save(new UntisCacheFetchState
+            {
+                Id = state?.Id ?? Guid.NewGuid(), ClassName = className, Kind = UntisCacheKind.Roster,
+                HotWindowFetchedAt = DateTime.UtcNow,
+            });
+        }
+        return rosterCache.GetByClass(className);
+    }
+
+    private static bool NeedsRefresh(UntisCacheFetchState? state, bool forceRefresh, DateTime utcNow) =>
+        forceRefresh || state?.HotWindowFetchedAt is null || utcNow - state.HotWindowFetchedAt >= HotWindowRefreshInterval;
+
+    public async Task<IReadOnlyList<UntisClassAbsenceEntryDto>> GetAbsencesAsync(string className,
+        DateOnly start, DateOnly end, bool forceRefresh = false, CancellationToken token = default)
+    {
+        var state = fetchState.Get(className, UntisCacheKind.Absences);
+        var plan = Plan(state, start, end, Today(), forceRefresh, DateTime.UtcNow);
+
+        if (plan.RefreshHotWindow)
+        {
+            var fresh = await untis.GetClassAbsencesAsync(className, plan.HotWindowStart, plan.HotWindowEnd, token);
+            absenceCache.ReplaceRange(className, Int(plan.HotWindowStart), Int(plan.HotWindowEnd), fresh.Select(ToEntry));
+        }
+        if (plan.FetchColdRange)
+        {
+            var older = await untis.GetClassAbsencesAsync(className, plan.ColdRangeStart, plan.ColdRangeEnd, token);
+            absenceCache.InsertRange(older.Select(ToEntry));
+        }
+        if (plan.RefreshHotWindow || plan.FetchColdRange)
+            fetchState.Save(NextState(state, className, UntisCacheKind.Absences, plan));
+
+        return absenceCache.GetByClassAndRange(className, Int(start), Int(end)).Select(ToDto).ToList();
+    }
+
+    public async Task<IReadOnlyList<UntisForeignClassRegisterEventDto>> GetClassRegisterEventsAsync(
+        string className, DateOnly start, DateOnly end, bool forceRefresh = false, CancellationToken token = default)
+    {
+        var state = fetchState.Get(className, UntisCacheKind.ClassRegister);
+        var plan = Plan(state, start, end, Today(), forceRefresh, DateTime.UtcNow);
+
+        if (plan.RefreshHotWindow)
+        {
+            var fresh = await untis.GetForeignClassRegisterEventsAsync(className, plan.HotWindowStart, plan.HotWindowEnd, token);
+            classRegisterCache.ReplaceRange(className, Int(plan.HotWindowStart), Int(plan.HotWindowEnd), fresh.Select(ToEntry));
+        }
+        if (plan.FetchColdRange)
+        {
+            var older = await untis.GetForeignClassRegisterEventsAsync(className, plan.ColdRangeStart, plan.ColdRangeEnd, token);
+            classRegisterCache.InsertRange(older.Select(ToEntry));
+        }
+        if (plan.RefreshHotWindow || plan.FetchColdRange)
+            fetchState.Save(NextState(state, className, UntisCacheKind.ClassRegister, plan));
+
+        return classRegisterCache.GetByClassAndRange(className, Int(start), Int(end)).Select(ToDto).ToList();
+    }
+
+    /// Reine Entscheidungslogik ohne Repository-/HTTP-Zugriff: was muss für eine Anfrage
+    /// [<paramref name="requestStart"/>..<paramref name="requestEnd"/>] live nachgeladen werden,
+    /// gegeben den zuletzt gespeicherten Zustand. Das heiße Fenster ist immer fest
+    /// [<paramref name="today"/> − <see cref="HotWindowDays"/>, <paramref name="today"/>], unabhängig
+    /// von der angefragten Spanne. Nach einem heißen Refresh reicht die bekannte Abdeckung mindestens
+    /// bis zum Fensteranfang zurück; ein zusätzlicher kalter Abruf erweitert sie nur so weit wie
+    /// für <paramref name="requestStart"/> nötig, nie weiter.
+    public static UntisCacheRefreshPlan Plan(UntisCacheFetchState? state, DateOnly requestStart, DateOnly requestEnd,
+        DateOnly today, bool forceRefresh, DateTime utcNow)
+    {
+        var hotStart = today.AddDays(-HotWindowDays);
+        var refreshHot = requestEnd >= hotStart && (forceRefresh || state?.HotWindowFetchedAt is null
+            || utcNow - state.HotWindowFetchedAt >= HotWindowRefreshInterval);
+
+        int? coverageStart = state?.ColdCoverageStartDate;
+        if (refreshHot)
+            coverageStart = coverageStart is { } existing ? Math.Min(existing, Int(hotStart)) : Int(hotStart);
+
+        var coldEnd = coverageStart is { } covered ? FromInt(covered).AddDays(-1) : hotStart.AddDays(-1);
+        var fetchCold = (coverageStart is null || requestStart < FromInt(coverageStart.Value)) && requestStart <= coldEnd;
+        if (fetchCold) coverageStart = Int(requestStart);
+
+        return new UntisCacheRefreshPlan(refreshHot, hotStart, today, fetchCold, requestStart, coldEnd, coverageStart);
+    }
+
+    private static UntisCacheFetchState NextState(UntisCacheFetchState? previous, string className,
+        UntisCacheKind kind, UntisCacheRefreshPlan plan) => new()
+    {
+        Id = previous?.Id ?? Guid.NewGuid(),
+        ClassName = className,
+        Kind = kind,
+        HotWindowFetchedAt = plan.RefreshHotWindow ? DateTime.UtcNow : previous?.HotWindowFetchedAt,
+        ColdCoverageStartDate = plan.ResultingColdCoverageStartDate,
+    };
+
+    private static DateOnly Today() => DateOnly.FromDateTime(DateTime.Today);
+    private static int Int(DateOnly date) => date.Year * 10000 + date.Month * 100 + date.Day;
+    private static DateOnly FromInt(int value) => new(value / 10000, value / 100 % 100, value % 100);
+
+    private static UntisAbsenceCacheEntry ToEntry(UntisClassAbsenceEntryDto x) => new()
+    {
+        ClassName = x.ClassName, StudentName = x.StudentName, ExternKey = x.ExternKey, Date = x.Date,
+        AbsentPeriods = x.AbsentPeriods, AbsentMinutes = x.AbsentMinutes, TeacherUsernames = x.TeacherUsernames,
+        Subject = x.Subject, AbsenceReason = x.AbsenceReason, Note = x.Note, EntryId = x.EntryId,
+        HandledOn = x.HandledOn, Counts = x.Counts, ExcuseNote = x.ExcuseNote, PeriodNumber = x.PeriodNumber,
+        Status = x.Status, CountsAsFullDay = x.CountsAsFullDay,
+    };
+
+    private static UntisClassAbsenceEntryDto ToDto(UntisAbsenceCacheEntry e) => new(
+        e.StudentName, e.ExternKey, e.ClassName, e.Date, e.AbsentPeriods, e.AbsentMinutes, e.TeacherUsernames,
+        e.Subject, e.AbsenceReason, e.Note, e.EntryId, e.HandledOn, e.Counts, e.ExcuseNote, e.PeriodNumber,
+        e.Status, e.CountsAsFullDay);
+
+    private static UntisClassRegisterCacheEntry ToEntry(UntisForeignClassRegisterEventDto x) => new()
+    {
+        ClassName = x.ClassName, Date = x.Date, Subject = x.Subject, StudentName = x.StudentName,
+        TeacherUsername = x.TeacherUsername, CategoryName = x.CategoryName, CategoryGroup = x.CategoryGroup,
+        Text = x.Text,
+    };
+
+    private static UntisForeignClassRegisterEventDto ToDto(UntisClassRegisterCacheEntry e) => new(
+        e.ClassName, e.Date, e.Subject, e.StudentName, e.TeacherUsername, e.CategoryName, e.CategoryGroup, e.Text);
+}

LehrerApp.Desktop/Services/WebUntisIntegrationService.cs

@@ -0,0 +1,243 @@
+using LehrerApp.WebUntis;
+
+namespace LehrerApp.Desktop.Services;
+
+public sealed class WebUntisIntegrationException(string message) : Exception(message);
+
+public sealed record UntisSchoolYearDto(int UntisId, string Name, int StartDate, int EndDate);
+public sealed record UntisHolidayDto(int UntisId, string Name, string? LongName, int StartDate, int EndDate);
+public sealed record UntisClassDto(int UntisId, string Name, string? LongName);
+public sealed record UntisTeacherDto(int UntisId, string Name, string? ForeName, string? LongName, string? Title,
+    bool Active, IReadOnlyList<int> DepartmentUntisIds)
+{
+    public string DisplayName => string.IsNullOrWhiteSpace(LongName)
+        ? Name
+        : $"{ForeName} {LongName} ({Name})".Trim();
+}
+public sealed record UntisEntityDto(int Id, string Name, int? OriginalId, string? OriginalName, string? ExternalKey);
+public sealed record UntisTimeUnitDto(string Name, int StartTime, int EndTime);
+public sealed record UntisTimeGridDayDto(int Day, IReadOnlyList<UntisTimeUnitDto> TimeUnits);
+public sealed record UntisTimetablePeriodDto(int Id, int Date, int StartTime, int EndTime, string? Code,
+    string? ActivityType, string? Info, string? LessonText, string? SubstitutionText, string? StudentGroup,
+    IReadOnlyList<UntisEntityDto> Classes, IReadOnlyList<UntisEntityDto> Teachers,
+    IReadOnlyList<UntisEntityDto> Subjects, IReadOnlyList<UntisEntityDto> Rooms);
+public sealed record UntisStudentAddressDto(string? Email, string? Mobile, string? Phone, string? City,
+    string? PostCode, string? Street);
+public sealed record UntisStudentDto(int UntisId, int? ExternKey, string ClassName, string? Name, string? LongName,
+    string? ForeName, string DisplayName, string? Gender, int? BirthDate, string? BirthDateRaw, int? EntryDate,
+    string? EntryDateRaw, int? ExitDate, string? ExitDateRaw, string? Text, string? MedicalReportDuty,
+    string? Schulpflicht, string? Majority, UntisStudentAddressDto Address, string? AttributeIL);
+public sealed record UntisStudentReportDto(int Count, string? ClassNameFilter, IReadOnlyList<UntisStudentDto> Students);
+public sealed record UntisLessonAbsenceDto(string StudentName, int Date, int AbsentPeriods,
+    int UnexcusedAbsentPeriods, int AbsentMinutes, int UnexcusedAbsentMinutes, int? StartTime, int? EndTime,
+    string? Reason, int? ExternKey, bool ExternKeyInParentheses, string? HandledOn, bool Counts);
+public sealed record UntisClassRegisterEventDto(string ClassName, int Date, string? Subject,
+    string StudentName, string? CategoryName, string? CategoryGroup, string? Text);
+public sealed record UntisForeignClassRegisterEventDto(string ClassName, int Date, string? Subject,
+    string StudentName, string? TeacherUsername, string? CategoryName, string? CategoryGroup, string? Text);
+public sealed record UntisClassAbsenceEntryDto(string StudentName, int? ExternKey, string ClassName, int Date,
+    int AbsentPeriods, int AbsentMinutes, string? TeacherUsernames, string? Subject, string? AbsenceReason,
+    string? Note, int? EntryId, string? HandledOn, bool Counts, string? ExcuseNote, int? PeriodNumber,
+    string? Status, bool CountsAsFullDay);
+
+/// <summary>Direkter WebUntis-Client des Desktops. Personenbezogene Antworten und der
+/// unverschlüsselte CSV-Report passieren zu keinem Zeitpunkt den LehrerApp-Server.</summary>
+public sealed class WebUntisIntegrationService(HttpClient http, WebUntisSettingsService settings) : IAsyncDisposable
+{
+    private readonly SemaphoreSlim _clientGate = new(1, 1);
+    private WebUntisClient? _client;
+
+    public bool IsAvailable => settings.ApiIsConfigured;
+
+    public async Task ConnectAsync(WebUntisCredentials credentials, CancellationToken token = default)
+    {
+        var candidate = CreateClient(credentials);
+        try
+        {
+            await candidate.GetSchoolYearsAsync(token);
+        }
+        catch (Exception exception) when (IsUntisError(exception))
+        {
+            await candidate.DisposeAsync();
+            throw Translate(exception);
+        }
+
+        WebUntisClient? previous;
+        await _clientGate.WaitAsync(token).ConfigureAwait(false);
+        try { previous = _client; _client = candidate; }
+        finally { _clientGate.Release(); }
+        if (previous is not null) await previous.DisposeAsync().ConfigureAwait(false);
+    }
+
+    public async Task DisconnectAsync(CancellationToken token = default)
+    {
+        WebUntisClient? previous;
+        await _clientGate.WaitAsync(token).ConfigureAwait(false);
+        try { previous = _client; _client = null; }
+        finally { _clientGate.Release(); }
+        if (previous is not null) await previous.DisposeAsync().ConfigureAwait(false);
+    }
+
+    public Task<IReadOnlyList<UntisSchoolYearDto>> GetSchoolYearsAsync(CancellationToken token = default) => ExecuteAsync(
+        async client => (IReadOnlyList<UntisSchoolYearDto>)(await client.GetSchoolYearsAsync(token))
+            .Select(x => new UntisSchoolYearDto(x.UntisId, x.Name, x.StartDate, x.EndDate)).ToList(), token);
+
+    public Task<IReadOnlyList<UntisHolidayDto>> GetHolidaysAsync(CancellationToken token = default) => ExecuteAsync(
+        async client => (IReadOnlyList<UntisHolidayDto>)(await client.GetHolidaysAsync(token))
+            .Select(x => new UntisHolidayDto(x.UntisId, x.Name, x.LongName, x.StartDate, x.EndDate)).ToList(), token);
+
+    public Task<IReadOnlyList<UntisClassDto>> GetClassesAsync(int schoolYearId, CancellationToken token = default) => ExecuteAsync(
+        async client => (IReadOnlyList<UntisClassDto>)(await client.GetClassesAsync(schoolYearId, token))
+            .Select(x => new UntisClassDto(x.UntisId, x.Name, x.LongName)).ToList(), token);
+
+    public Task<IReadOnlyList<UntisTeacherDto>> GetTeachersAsync(CancellationToken token = default) => ExecuteAsync(
+        async client => (IReadOnlyList<UntisTeacherDto>)(await client.GetTeachersAsync(token))
+            .Select(x => new UntisTeacherDto(x.UntisId, x.Name, x.ForeName, x.LongName, x.Title, x.Active,
+                x.DepartmentUntisIds)).ToList(), token);
+
+    public Task<IReadOnlyList<UntisTimeGridDayDto>> GetTimeGridAsync(CancellationToken token = default) => ExecuteAsync(
+        async client => (IReadOnlyList<UntisTimeGridDayDto>)(await client.GetTimeGridAsync(token))
+            .Select(x => new UntisTimeGridDayDto(x.Day,
+                x.TimeUnits.Select(t => new UntisTimeUnitDto(t.Name, t.StartTime, t.EndTime)).ToList())).ToList(), token);
+
+    public Task<IReadOnlyList<UntisTimetablePeriodDto>> GetTimetableAsync(int teacherId, DateOnly start,
+        DateOnly end, CancellationToken token = default) => ExecuteAsync(async client =>
+            (IReadOnlyList<UntisTimetablePeriodDto>)(await client.GetTimetableAsync(
+                UntisTimetableElementType.Teacher, teacherId, Date(start), Date(end), token))
+            .Select(x => new UntisTimetablePeriodDto(x.Id, x.Date, x.StartTime, x.EndTime, x.Code,
+                x.ActivityType, x.Info, x.LessonText, x.SubstitutionText, x.StudentGroup,
+                Entities(x.Classes), Entities(x.Teachers), Entities(x.Subjects), Entities(x.Rooms))).ToList(), token);
+
+    public Task<UntisStudentReportDto> GetStudentsAsync(string className, CancellationToken token = default) => ExecuteAsync(
+        async client =>
+        {
+            var report = await client.GetStudentReportAsync(className, token);
+            return new UntisStudentReportDto(report.Count, report.ClassNameFilter, report.Students.Select(x =>
+                new UntisStudentDto(x.UntisId, x.ExternKey, x.ClassName, x.Name, x.LongName, x.ForeName,
+                    x.DisplayName, x.Gender, x.BirthDate, x.BirthDateRaw, x.EntryDate, x.EntryDateRaw,
+                    x.ExitDate, x.ExitDateRaw, x.Text, x.MedicalReportDuty, x.Schulpflicht, x.Majority,
+                    new UntisStudentAddressDto(x.Address.Email, x.Address.Mobile, x.Address.Phone, x.Address.City,
+                        x.Address.PostCode, x.Address.Street), x.AttributeIL)).ToList());
+        }, token);
+
+    public Task<IReadOnlyList<UntisLessonAbsenceDto>> GetLessonAbsencesAsync(int lessonId,
+        DateOnly start, DateOnly end, CancellationToken token = default) => ExecuteAsync(async client =>
+    {
+        var absences = await client.GetLessonAbsencesAsync(lessonId, Date(start), Date(end), token);
+        return (IReadOnlyList<UntisLessonAbsenceDto>)absences.Select(x => new UntisLessonAbsenceDto(
+            x.StudentName, x.Date, x.AbsentPeriods, x.UnexcusedAbsentPeriods, x.AbsentMinutes,
+            x.UnexcusedAbsentMinutes, x.StartTime, x.EndTime, x.Reason, x.ExternKey, x.ExternKeyInParentheses,
+            x.HandledOn, x.Counts)).ToList();
+    }, token);
+
+    // "-alle-"-Bericht, hier auf eigene Einträge gefiltert (Benutzer == eigener WebUntis-Login) - Einträge
+    // anderer Lehrkräfte zu Schülern der eigenen Klasse gehören zu einem eigenständigen, noch nicht
+    // gebauten "Klassenlehrer"-Feature (siehe TODO.md), nicht zum reinen Dokumentations-Abgleich.
+    public Task<IReadOnlyList<UntisClassRegisterEventDto>> GetOwnClassRegisterEventsAsync(DateOnly start,
+        DateOnly end, CancellationToken token = default) => ExecuteAsync(async client =>
+    {
+        var ownUsername = settings.GetApiCredentials()?.Username;
+        var entries = await client.GetClassRegisterEventsReportAsync(Date(start), Date(end), token);
+        return (IReadOnlyList<UntisClassRegisterEventDto>)entries
+            .Where(x => ownUsername is not null
+                        && string.Equals(x.TeacherUsername, ownUsername, StringComparison.OrdinalIgnoreCase))
+            .Select(x => new UntisClassRegisterEventDto(x.ClassName, x.Date, x.Subject, x.StudentName,
+                x.CategoryName, x.CategoryGroup, x.Text))
+            .ToList();
+    }, token);
+
+    // Spiegelbild von GetOwnClassRegisterEventsAsync für das "Klassenlehrer"-Feature (siehe TODO.md):
+    // dieselben "-alle-"-Rohdaten, aber Einträge anderer Lehrkräfte statt der eigenen, zusätzlich auf
+    // die übergebene Klasse eingeschränkt (der "-alle-"-Bericht liefert sonst auch andere Klassen mit,
+    // sobald eine Lehrkraft mehrere Klassen unterrichtet).
+    public Task<IReadOnlyList<UntisForeignClassRegisterEventDto>> GetForeignClassRegisterEventsAsync(
+        string className, DateOnly start, DateOnly end, CancellationToken token = default) => ExecuteAsync(async client =>
+    {
+        var ownUsername = settings.GetApiCredentials()?.Username;
+        var entries = await client.GetClassRegisterEventsReportAsync(Date(start), Date(end), token);
+        return (IReadOnlyList<UntisForeignClassRegisterEventDto>)entries
+            .Where(x => string.Equals(x.ClassName, className, StringComparison.OrdinalIgnoreCase)
+                        // Nicht einfach "!=" gegen ownUsername: wäre ownUsername unbekannt (null), würde
+                        // ein ebenfalls fehlender TeacherUsername sonst fälschlich als "eigen" erkannt
+                        // (Equals(null,null)==true) und rausgefiltert statt als fremd angezeigt zu werden.
+                        && !(ownUsername is not null
+                             && string.Equals(x.TeacherUsername, ownUsername, StringComparison.OrdinalIgnoreCase)))
+            .Select(x => new UntisForeignClassRegisterEventDto(x.ClassName, x.Date, x.Subject, x.StudentName,
+                x.TeacherUsername, x.CategoryName, x.CategoryGroup, x.Text))
+            .ToList();
+    }, token);
+
+    // Fehlzeiten der ganzen Klasse über alle Fächer, Ergänzung zu GetForeignClassRegisterEventsAsync
+    // für das "Klassenlehrer"-Feature. Der Bericht adressiert die Klasse über "KL"+getKlassen-ID statt
+    // eines Namens, siehe ResolveClassIdAsync.
+    public Task<IReadOnlyList<UntisClassAbsenceEntryDto>> GetClassAbsencesAsync(string className,
+        DateOnly start, DateOnly end, CancellationToken token = default) => ExecuteAsync(async client =>
+    {
+        var classId = await ResolveClassIdAsync(client, className, token);
+        var entries = await client.GetClassAbsencesAsync(classId, Date(start), Date(end), token);
+        return (IReadOnlyList<UntisClassAbsenceEntryDto>)entries.Select(x => new UntisClassAbsenceEntryDto(
+            x.StudentName, x.ExternKey, x.ClassName, x.Date, x.AbsentPeriods, x.AbsentMinutes,
+            x.TeacherUsernames, x.Subject, x.AbsenceReason, x.Note, x.EntryId, x.HandledOn, x.Counts,
+            x.ExcuseNote, x.PeriodNumber, x.Status, x.CountsAsFullDay))
+            .ToList();
+    }, token);
+
+    // "KL" + getKlassen-ID, dasselbe Element-Kürzel-Schema wie kl/te/su/ro bei anderen Berichten
+    // (siehe Entities(...) unten). Unbestätigt (kein offizieller Report-Parameter dokumentiert), aber
+    // aus einem echten Browser-Request rückgeschlossen - schlägt die Zuordnung fehl, liefert der
+    // Bericht erkennbar leere/falsche Daten statt eines stillen Fehlers.
+    private static async Task<string> ResolveClassIdAsync(WebUntisClient client, string className,
+        CancellationToken token)
+    {
+        var years = await client.GetSchoolYearsAsync(token);
+        var today = Date(DateOnly.FromDateTime(DateTime.Today));
+        var year = years.FirstOrDefault(y => y.StartDate <= today && y.EndDate >= today)
+            ?? years.OrderByDescending(y => y.StartDate).FirstOrDefault()
+            ?? throw new WebUntisIntegrationException("WebUntis hat kein Schuljahr geliefert.");
+        var classes = await client.GetClassesAsync(year.UntisId, token);
+        var matches = classes.Where(c => string.Equals(c.Name, className, StringComparison.OrdinalIgnoreCase)).ToList();
+        return matches.Count switch
+        {
+            1 => $"KL{matches[0].UntisId}",
+            0 => throw new WebUntisIntegrationException($"WebUntis kennt keine Klasse namens \"{className}\"."),
+            _ => throw new WebUntisIntegrationException(
+                $"Mehrere WebUntis-Klassen heißen \"{className}\" - bitte manuell prüfen."),
+        };
+    }
+
+    private async Task<T> ExecuteAsync<T>(Func<WebUntisClient, Task<T>> operation, CancellationToken token)
+    {
+        try { return await operation(await GetClientAsync(token)); }
+        catch (Exception exception) when (IsUntisError(exception)) { throw Translate(exception); }
+    }
+
+    private async Task<WebUntisClient> GetClientAsync(CancellationToken token)
+    {
+        if (_client is not null) return _client;
+        await _clientGate.WaitAsync(token);
+        try
+        {
+            if (_client is not null) return _client;
+            var credentials = settings.GetApiCredentials()
+                ?? throw new WebUntisIntegrationException("Bitte zuerst die WebUntis-Anmeldedaten einrichten.");
+            return _client = CreateClient(credentials);
+        }
+        finally { _clientGate.Release(); }
+    }
+
+    private WebUntisClient CreateClient(WebUntisCredentials credentials) => new(http, new WebUntisOptions
+    {
+        School = credentials.School, Host = credentials.Host, Username = credentials.Username,
+        Password = credentials.Password, Client = "LehrerApp-Desktop", SessionIdleTimeoutMinutes = 10,
+    });
+
+    private static int Date(DateOnly date) => date.Year * 10000 + date.Month * 100 + date.Day;
+    private static IReadOnlyList<UntisEntityDto> Entities(IReadOnlyList<UntisEntity> values) => values
+        .Select(x => new UntisEntityDto(x.Id, x.Name, x.OriginalId, x.OriginalName, x.ExternalKey)).ToList();
+    private static bool IsUntisError(Exception exception) => exception is WebUntisException
+        or WebUntisConfigurationException or InvalidDataException;
+    private static WebUntisIntegrationException Translate(Exception exception) =>
+        new(exception.Message);
+
+    public async ValueTask DisposeAsync() => await DisconnectAsync().ConfigureAwait(false);
+}

LehrerApp.Desktop/Services/WebUntisSettingsService.cs

@@ -9,8 +9,21 @@ internal class WebUntisSettingsConfig
     public string? EncryptedIcalUrl { get; set; }
     public DateTime? LastSyncAt { get; set; }
     public string LastSyncStatus { get; set; } = "";
+    public string? EncryptedApiCredentials { get; set; }
+    public int? TeacherUntisId { get; set; }
+    public int? HomeroomClassUntisId { get; set; }
+    public string? HomeroomClassName { get; set; }
+    public List<CachedUntisHoliday>? CachedHolidays { get; set; }
+    public DateTime? HolidaysFetchedAt { get; set; }
 }
 
+public sealed record WebUntisCredentials(string School, string Host, string Username, string Password);
+
+/// <summary>Ferienzeitraum aus WebUntis' <c>getHolidays</c>-Bericht, hier auf die für die
+/// Fehlquoten-Berechnung ("Klassenlehrer"-Feature) relevanten Felder reduziert. Kein Geheimnis
+/// (anders als iCal-URL/API-Zugangsdaten in dieser Datei), deshalb unverschlüsselt gecacht.</summary>
+public sealed record CachedUntisHoliday(string Name, DateOnly Start, DateOnly End);
+
 /// <summary>
 /// Einstellungen für den WebUntis-iCal-Abgleich (Nutzer-Feedback, siehe TODO.md). Liegt wie
 /// AiSettingsService/SyncSettingsService in LehrerApp.Desktop statt LehrerApp.Core, da die
@@ -30,6 +43,10 @@ public class WebUntisSettingsService
 
     public bool Enabled => _config.Enabled;
     public bool IsConfigured => _config.EncryptedIcalUrl is not null;
+    public bool ApiIsConfigured => _config.EncryptedApiCredentials is not null;
+    public int? TeacherUntisId => _config.TeacherUntisId;
+    public int? HomeroomClassUntisId => _config.HomeroomClassUntisId;
+    public string? HomeroomClassName => _config.HomeroomClassName;
     public DateTime? LastSyncAt => _config.LastSyncAt;
     public string LastSyncStatus => _config.LastSyncStatus;
 
@@ -63,6 +80,41 @@ public class WebUntisSettingsService
         Save();
     }
 
+    public void SetApiCredentials(WebUntisCredentials credentials)
+    {
+        _config.EncryptedApiCredentials = SyncCrypto.EncryptObject(credentials, _urlKey);
+        Save();
+    }
+
+    public WebUntisCredentials? GetApiCredentials() => _config.EncryptedApiCredentials is null
+        ? null
+        : SyncCrypto.DecryptObject<WebUntisCredentials>(_config.EncryptedApiCredentials, _urlKey);
+
+    public void ClearApiCredentials()
+    {
+        _config.EncryptedApiCredentials = null;
+        _config.TeacherUntisId = null;
+        _config.HomeroomClassUntisId = null;
+        _config.HomeroomClassName = null;
+        Save();
+    }
+
+    public void SetTeacherUntisId(int? teacherUntisId)
+    {
+        _config.TeacherUntisId = teacherUntisId;
+        Save();
+    }
+
+    // Die Klasse, deren Klassenlehrer/-in man ist - unabhängig von jeder LearningGroup (siehe
+    // TODO.md "Klassenlehrer"-Feature): man ist es für die ganze Klasse, nicht für einen einzelnen
+    // Unterricht/Kurs. HomeroomClassName ist wie TeacherUntisId unverschlüsselt, da kein Geheimnis.
+    public void SetHomeroomClass(int? untisId, string? name)
+    {
+        _config.HomeroomClassUntisId = untisId;
+        _config.HomeroomClassName = name;
+        Save();
+    }
+
     public void SetLastSync(DateTime at, string status)
     {
         _config.LastSyncAt = at;
@@ -70,6 +122,16 @@ public class WebUntisSettingsService
         Save();
     }
 
+    public DateTime? HolidaysFetchedAt => _config.HolidaysFetchedAt;
+    public IReadOnlyList<CachedUntisHoliday>? GetCachedHolidays() => _config.CachedHolidays;
+
+    public void SetCachedHolidays(IReadOnlyList<CachedUntisHoliday> holidays, DateTime at)
+    {
+        _config.CachedHolidays = holidays.ToList();
+        _config.HolidaysFetchedAt = at;
+        Save();
+    }
+
     private byte[] GenerateAndSaveKey()
     {
         var key = SyncCrypto.GenerateKey();

LehrerApp.Desktop/Styles/SemanticBrushes.axaml

@@ -0,0 +1,74 @@
+<ResourceDictionary xmlns="https://github.com/avaloniaui"
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+  <!--
+    Semantische Pinsel für Flächen und Statusfarben (Klassenlehrer-Bereich, perspektivisch auch
+    die übrigen Ansichten). Hart codierte Hex-Werte in den Views waren auf das dunkle Theme
+    zugeschnitten und blieben beim Umschalten auf "Hell" stehen — dunkle Kartenflächen auf hellem
+    Fenstergrund, Statustexte ohne Kontrast. Über ThemeDictionaries tauscht Avalonia die Werte beim
+    Theme-Wechsel live aus, sofern die Views sie per DynamicResource (nicht StaticResource) holen.
+  -->
+  <ResourceDictionary.ThemeDictionaries>
+
+    <ResourceDictionary x:Key="Dark">
+      <!-- Flächen -->
+      <SolidColorBrush x:Key="AppCardBackgroundBrush" Color="#11151B"/>
+      <SolidColorBrush x:Key="AppCardBorderBrush" Color="#2A3038"/>
+      <SolidColorBrush x:Key="AppListRowBackgroundBrush" Color="#0E1217"/>
+      <SolidColorBrush x:Key="AppListRowHoverBrush" Color="#171D25"/>
+      <SolidColorBrush x:Key="AppListRowBorderBrush" Color="#262C34"/>
+      <SolidColorBrush x:Key="AppTrackBackgroundBrush" Color="#252B33"/>
+      <SolidColorBrush x:Key="AppChipBackgroundBrush" Color="#1C222A"/>
+      <SolidColorBrush x:Key="AppAvatarBorderBrush" Color="#4A515C"/>
+      <!-- Akzent -->
+      <SolidColorBrush x:Key="AppAccentTextBrush" Color="#5795F5"/>
+      <SolidColorBrush x:Key="AppAccentSoftBackgroundBrush" Color="#173765"/>
+      <SolidColorBrush x:Key="AppAccentOnSoftBrush" Color="#66A3FF"/>
+      <SolidColorBrush x:Key="AppFilterBorderBrush" Color="#343B45"/>
+      <SolidColorBrush x:Key="AppFilterActiveBackgroundBrush" Color="#173765"/>
+      <SolidColorBrush x:Key="AppFilterActiveBorderBrush" Color="#3C86F7"/>
+      <SolidColorBrush x:Key="AppFilterActiveForegroundBrush" Color="#FFFFFF"/>
+      <!-- Status: Nutzer-Feedback (August 2026) — Warnung (Amber) und Gefahr (Korallrot) waren
+           auf dem Bildschirm kaum auseinanderzuhalten. Per scripts/validate_palette.js der
+           dataviz-Skill gegen AppTrackBackgroundBrush/AppCardBackgroundBrush geprüft (adjacent
+           pairs, wie sie im gestapelten Balken tatsächlich aneinanderstoßen): die alte Kombi
+           lag bei ΔE nur 4.6–10.8 (protan/deutan), jetzt 10.2–24.4 — deutlich über der
+           Zielschwelle von 8. Ok/Warnung mussten zusätzlich im Tagesüberblick-Balken die
+           Reihenfolge tauschen (Info dazwischen), weil Grün und das validierte Dunkel-Gelb sonst
+           direkt aneinanderstießen (ΔE nur 3.0 unter Protanopie) — siehe
+           ClassTeacherOverviewView.axaml.
+           good=#008300, warning(dunkel)=#c98500, warning(hell)=#eda100, critical=#d03b3b
+           sind dieselben Stufen wie die validierte Kategorial-/Statuspalette der dataviz-Skill;
+           bewusst nicht wieder frei gewählt, um nicht erneut ins selbe Problem zu laufen. -->
+      <SolidColorBrush x:Key="AppStatusOkBrush" Color="#008300"/>
+      <SolidColorBrush x:Key="AppStatusInfoBrush" Color="#3987E5"/>
+      <SolidColorBrush x:Key="AppStatusWarningBrush" Color="#C98500"/>
+      <SolidColorBrush x:Key="AppStatusDangerBrush" Color="#D03B3B"/>
+    </ResourceDictionary>
+
+    <ResourceDictionary x:Key="Light">
+      <!-- Flächen: Karten heben sich hier heller vom grauen Fenstergrund ab, nicht dunkler. -->
+      <SolidColorBrush x:Key="AppCardBackgroundBrush" Color="#FFFFFF"/>
+      <SolidColorBrush x:Key="AppCardBorderBrush" Color="#DCE1E8"/>
+      <SolidColorBrush x:Key="AppListRowBackgroundBrush" Color="#FFFFFF"/>
+      <SolidColorBrush x:Key="AppListRowHoverBrush" Color="#EDF2F9"/>
+      <SolidColorBrush x:Key="AppListRowBorderBrush" Color="#E3E7ED"/>
+      <SolidColorBrush x:Key="AppTrackBackgroundBrush" Color="#E3E7ED"/>
+      <SolidColorBrush x:Key="AppChipBackgroundBrush" Color="#EDF0F5"/>
+      <SolidColorBrush x:Key="AppAvatarBorderBrush" Color="#B7BEC9"/>
+      <!-- Akzent: dunklere Töne, die Akzentfarben aus dem Dark-Theme wären auf Weiß zu blass. -->
+      <SolidColorBrush x:Key="AppAccentTextBrush" Color="#1B5FC7"/>
+      <SolidColorBrush x:Key="AppAccentSoftBackgroundBrush" Color="#DCE9FC"/>
+      <SolidColorBrush x:Key="AppAccentOnSoftBrush" Color="#14509F"/>
+      <SolidColorBrush x:Key="AppFilterBorderBrush" Color="#C7CDD6"/>
+      <SolidColorBrush x:Key="AppFilterActiveBackgroundBrush" Color="#D7E6FC"/>
+      <SolidColorBrush x:Key="AppFilterActiveBorderBrush" Color="#2C6FD8"/>
+      <SolidColorBrush x:Key="AppFilterActiveForegroundBrush" Color="#10243F"/>
+      <!-- Status: siehe Dark-Kommentar oben — dieselbe Validierung, helle Stufen. -->
+      <SolidColorBrush x:Key="AppStatusOkBrush" Color="#008300"/>
+      <SolidColorBrush x:Key="AppStatusInfoBrush" Color="#2A78D6"/>
+      <SolidColorBrush x:Key="AppStatusWarningBrush" Color="#EDA100"/>
+      <SolidColorBrush x:Key="AppStatusDangerBrush" Color="#D03B3B"/>
+    </ResourceDictionary>
+
+  </ResourceDictionary.ThemeDictionaries>
+</ResourceDictionary>

LehrerApp.Desktop/ViewModels/ClassTeacher/ClassTeacherDetailsViewModel.cs

@@ -0,0 +1,252 @@
+using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Desktop.Services;
+
+namespace LehrerApp.Desktop.ViewModels.ClassTeacher;
+
+/// <summary>Eine Zeile aus dem "-alle-"-Klassenbuchbericht, die eine andere Lehrkraft angelegt hat.
+/// Rein zur Ansicht - anders als beim Dokumentations-Abgleich (eigene Einträge) gibt es hier kein
+/// "Übernehmen", da es keine eigenen Einträge zum lokalen Synchronisieren sind.</summary>
+public sealed record ClassTeacherClassRegisterRow(DateOnly Date, string? Subject, string StudentName,
+    string? TeacherUsername, string? CategoryName, string? CategoryGroup, string? Text)
+{
+    public string DateLabel => Date.ToString("dd.MM.yyyy");
+    public string StudentDisplayName => DisplayName(StudentName);
+    public ClassTeacherStatusKind CategoryKind =>
+        CategoryGroup?.Contains("Negativ", StringComparison.OrdinalIgnoreCase) == true
+            ? ClassTeacherStatusKind.Danger : ClassTeacherStatusKind.Info;
+    public bool IsDangerStatus => CategoryKind == ClassTeacherStatusKind.Danger;
+    public bool IsInfoStatus => CategoryKind == ClassTeacherStatusKind.Info;
+
+    private static string DisplayName(string value)
+    {
+        var parts = value.Split(' ', StringSplitOptions.RemoveEmptyEntries);
+        return parts.Length < 2 ? value : string.Join(" ", parts.Skip(1).Append(parts[0]));
+    }
+}
+
+/// <summary>Zusammenfassung "wie oft welche Klassenbuch-Kategorie im Zeitraum, und bei wem am
+/// häufigsten" — Nutzer-Feedback: die reine Gesamtzahl ("12 Klassenbucheinträge") sagt wenig,
+/// eine Aufschlüsselung nach Kategorie ist die eigentlich interessante Information ("Hausaufgaben
+/// fehlen: 12×, davon 5× Ben"). Rein clientseitig aus den bereits geladenen <see cref="Entries"/>
+/// berechnet, kein zusätzlicher WebUntis-Abruf.</summary>
+public sealed record ClassTeacherCategoryAggregateRow(string CategoryName, int Count, string TopStudentsLabel)
+{
+    public string SummaryLabel => string.IsNullOrEmpty(TopStudentsLabel)
+        ? $"{Count}×" : $"{Count}× — {TopStudentsLabel}";
+
+    public static IReadOnlyList<ClassTeacherCategoryAggregateRow> Build(
+        IReadOnlyList<ClassTeacherClassRegisterRow> entries, int topStudentsPerCategory = 2) =>
+        entries.Where(e => !string.IsNullOrWhiteSpace(e.CategoryName))
+            .GroupBy(e => e.CategoryName!)
+            .Select(g =>
+            {
+                var topStudents = g.GroupBy(e => e.StudentDisplayName)
+                    .Select(sg => (Name: sg.Key, Count: sg.Count()))
+                    .OrderByDescending(sg => sg.Count).ThenBy(sg => sg.Name)
+                    .Take(topStudentsPerCategory)
+                    .Select(sg => $"{sg.Count}× {sg.Name}");
+                return new ClassTeacherCategoryAggregateRow(g.Key, g.Count(), string.Join(", ", topStudents));
+            })
+            .OrderByDescending(r => r.Count).ThenBy(r => r.CategoryName)
+            .ToList();
+}
+
+/// <summary>Fehlzeiten eines/einer Schüler*in an einem Tag, über alle Fächer zusammengefasst -
+/// der WebUntis-Bericht liefert eine Zeile pro Fehlstunde, was bei einer ganzen Klasse über mehrere
+/// Wochen zu unübersichtlich wäre (Nutzer-Feedback: kompakte "auf einen Blick"-Übersicht statt
+/// Rohdaten). Die Rohzeilen (<see cref="UntisClassAbsenceEntryDto"/>) bleiben trotzdem erreichbar,
+/// falls später ein Detail-Drill-down pro Schüler*in dazukommt (siehe TODO.md).</summary>
+public sealed record ClassAbsenceDaySummaryRow(DateOnly Date, string StudentName, int? ExternKey,
+    int TotalAbsentPeriods, int TotalAbsentMinutes, IReadOnlyList<string> Subjects,
+    IReadOnlyList<int> PeriodNumbers, IReadOnlyList<string> Statuses, IReadOnlyList<string> AbsenceReasons,
+    string? Note, string? ExcuseNote, bool CountsAsFullDay)
+{
+    public string DateLabel => Date.ToString("dd.MM.yyyy");
+    public string StudentDisplayName
+    {
+        get
+        {
+            var parts = StudentName.Split(' ', StringSplitOptions.RemoveEmptyEntries);
+            return parts.Length < 2 ? StudentName : string.Join(" ", parts.Skip(1).Append(parts[0]));
+        }
+    }
+    public string SubjectsLabel => string.Join(", ", Subjects);
+    public string PeriodsLabel => string.Join(", ", PeriodNumbers.Order());
+    public string StatusLabel => string.Join(", ", Statuses);
+    public string ReasonLabel => string.Join("; ", AbsenceReasons);
+    public bool IsLate => TotalAbsentPeriods == 0 || AbsenceReasons.Any(r =>
+        r.Contains("verspät", StringComparison.OrdinalIgnoreCase));
+    public bool IsUnexcused => Statuses.Any(s =>
+        s.Contains("nicht entsch", StringComparison.OrdinalIgnoreCase));
+    public string KindLabel => IsLate ? $"{TotalAbsentMinutes} Min. verspätet" :
+        CountsAsFullDay ? "Ganzer Fehltag" : $"{TotalAbsentPeriods} Fehlstunde{(TotalAbsentPeriods == 1 ? "" : "n")}";
+    public string FriendlyStatusLabel => IsUnexcused ? "Unentschuldigt" :
+        Statuses.Any(s => s.Contains("entsch", StringComparison.OrdinalIgnoreCase)) ? "Entschuldigt" : StatusLabel;
+    public ClassTeacherStatusKind StatusKind => IsUnexcused ? ClassTeacherStatusKind.Danger :
+        IsLate ? ClassTeacherStatusKind.Warning : ClassTeacherStatusKind.Ok;
+    public bool IsDangerStatus => StatusKind == ClassTeacherStatusKind.Danger;
+    public bool IsWarningStatus => StatusKind == ClassTeacherStatusKind.Warning;
+    public string DetailLabel => string.Join(" · ", new[] { ReasonLabel, Note, ExcuseNote }
+        .Where(value => !string.IsNullOrWhiteSpace(value)));
+
+    public static IReadOnlyList<ClassAbsenceDaySummaryRow> GroupByStudentAndDay(
+        IEnumerable<UntisClassAbsenceEntryDto> entries) => entries
+        .Select(e => (Entry: e, Date: TryDate(e.Date, out var d) ? d : (DateOnly?)null))
+        .Where(x => x.Date is not null)
+        .GroupBy(x => (Date: x.Date!.Value, x.Entry.StudentName, x.Entry.ExternKey))
+        .Select(g => new ClassAbsenceDaySummaryRow(
+            g.Key.Date, g.Key.StudentName, g.Key.ExternKey,
+            g.Sum(x => x.Entry.AbsentPeriods), g.Sum(x => x.Entry.AbsentMinutes),
+            Distinct(g.Select(x => x.Entry.Subject)),
+            g.Select(x => x.Entry.PeriodNumber).Where(p => p is not null).Select(p => p!.Value).Distinct().ToList(),
+            Distinct(g.Select(x => x.Entry.Status)),
+            Distinct(g.Select(x => x.Entry.AbsenceReason)),
+            g.Select(x => x.Entry.Note).FirstOrDefault(n => !string.IsNullOrWhiteSpace(n)),
+            g.Select(x => x.Entry.ExcuseNote).FirstOrDefault(n => !string.IsNullOrWhiteSpace(n)),
+            g.Any(x => x.Entry.CountsAsFullDay)))
+        .OrderByDescending(r => r.Date).ThenBy(r => r.StudentName)
+        .ToList();
+
+    private static List<string> Distinct(IEnumerable<string?> values) =>
+        values.Where(v => !string.IsNullOrWhiteSpace(v)).Select(v => v!).Distinct().ToList();
+
+    private static bool TryDate(int value, out DateOnly date) =>
+        DateOnly.TryParseExact(value.ToString(), "yyyyMMdd", out date);
+}
+
+/// <summary>
+/// Details-Ansicht des Klassenlehrer-Bereichs: Klassenbucheinträge, die andere Lehrkräfte zu
+/// Schülern der Klasse angelegt haben (WebUntis "-alle-"-Bericht, gefiltert auf fremde statt der
+/// eigenen Benutzerkennung wie beim bestehenden Dokumentations-Abgleich), sowie die Fehlzeiten der
+/// Klasse über alle Fächer — beide über <see cref="UntisReportCacheService"/> (lokal gecacht statt
+/// bei jedem Öffnen neu abgerufen, siehe TODO.md). Beides rein zur Ansicht, kein Übernehmen in
+/// lokale Daten. Bewusst unabhängig von jeder <see cref="Core.Models.LearningGroup"/> —
+/// Klassenlehrer ist man für die ganze Klasse, nicht für einen einzelnen Unterricht; die Klasse
+/// kommt aus <see cref="ClassTeacherOverviewViewModel"/> (letztlich aus den WebUntis-Einstellungen),
+/// nicht aus einer Gruppen-ID.
+/// </summary>
+public partial class ClassTeacherDetailsViewModel : ObservableObject
+{
+    private readonly UntisReportCacheService _cache;
+    private string _className = "";
+
+    public ObservableCollection<ClassTeacherClassRegisterRow> Entries { get; } = [];
+    public ObservableCollection<ClassAbsenceDaySummaryRow> AbsenceEntries { get; } = [];
+    public ObservableCollection<ClassTeacherCategoryAggregateRow> CategoryAggregates { get; } = [];
+
+    [ObservableProperty] private DateTimeOffset _startDate = DateTimeOffset.Now.AddDays(-6);
+    [ObservableProperty] private DateTimeOffset _endDate = DateTimeOffset.Now;
+    [ObservableProperty] private string _status = "Zeitraum wählen und laden.";
+    [ObservableProperty] private bool _busy;
+    /// Von der Übersicht gesetzt (Klick auf eine Roster-Zeile) - leer zeigt alle Schüler*innen.
+    [ObservableProperty] private string _studentFilter = "";
+    [ObservableProperty] private int _quickRangeIndex = 1;
+
+    public bool HasEntries => Entries.Count > 0;
+    public bool HasAbsenceEntries => AbsenceEntries.Count > 0;
+    public bool HasCategoryAggregates => CategoryAggregates.Count > 0;
+    public string ActiveFilterLabel => string.IsNullOrWhiteSpace(StudentFilter)
+        ? "Alle Schüler*innen" : StudentFilter;
+
+    public ClassTeacherDetailsViewModel(UntisReportCacheService cache)
+    {
+        _cache = cache;
+    }
+
+    public void Initialize(string className)
+    {
+        _className = className;
+        StudentFilter = "";
+        Entries.Clear();
+        AbsenceEntries.Clear();
+        CategoryAggregates.Clear();
+        Status = "Zeitraum wählen und laden.";
+        NotifyListState();
+    }
+
+    partial void OnStudentFilterChanged(string value) => OnPropertyChanged(nameof(ActiveFilterLabel));
+
+    partial void OnQuickRangeIndexChanged(int value)
+    {
+        var days = value switch { 0 => 0, 1 => 6, 2 => 29, _ => 6 };
+        EndDate = DateTimeOffset.Now;
+        StartDate = DateTimeOffset.Now.AddDays(-days);
+    }
+
+    [RelayCommand]
+    private Task Load() => LoadInternal(forceRefresh: false);
+
+    /// Umgeht bewusst die Stunden-Sperre von <see cref="UntisReportCacheService"/> — für den Fall,
+    /// dass man sicher weiß, dass sich seit dem letzten automatischen Abruf etwas geändert hat.
+    [RelayCommand]
+    private Task Refresh() => LoadInternal(forceRefresh: true);
+
+    [RelayCommand]
+    private Task ApplyFilter() => LoadInternal(forceRefresh: false);
+
+    [RelayCommand]
+    private async Task ClearStudentFilter()
+    {
+        StudentFilter = "";
+        await LoadInternal(forceRefresh: false);
+    }
+
+    private async Task LoadInternal(bool forceRefresh)
+    {
+        var start = DateOnly.FromDateTime(StartDate.LocalDateTime);
+        var end = DateOnly.FromDateTime(EndDate.LocalDateTime);
+        if (end < start) { Status = "Das Enddatum darf nicht vor dem Startdatum liegen."; return; }
+        if (string.IsNullOrWhiteSpace(_className)) { Status = "Keine Klasse ausgewählt."; return; }
+
+        Busy = true; Entries.Clear(); AbsenceEntries.Clear(); CategoryAggregates.Clear(); NotifyListState();
+        try
+        {
+            var classRegisterTask = _cache.GetClassRegisterEventsAsync(_className, start, end, forceRefresh);
+            var absencesTask = _cache.GetAbsencesAsync(_className, start, end, forceRefresh);
+            await Task.WhenAll(classRegisterTask, absencesTask);
+
+            var ordered = classRegisterTask.Result
+                .Where(MatchesStudentFilter)
+                .Select(e => (Entry: e, Date: TryDate(e.Date, out var d) ? d : (DateOnly?)null))
+                .Where(x => x.Date is not null)
+                .OrderByDescending(x => x.Date).ThenBy(x => x.Entry.StudentName);
+            foreach (var (entry, date) in ordered)
+            {
+                Entries.Add(new ClassTeacherClassRegisterRow(date!.Value, entry.Subject, entry.StudentName,
+                    entry.TeacherUsername, entry.CategoryName, entry.CategoryGroup, entry.Text));
+            }
+            foreach (var row in ClassTeacherCategoryAggregateRow.Build(Entries)) CategoryAggregates.Add(row);
+
+            var absences = absencesTask.Result.Where(MatchesStudentFilter);
+            foreach (var row in ClassAbsenceDaySummaryRow.GroupByStudentAndDay(absences))
+                AbsenceEntries.Add(row);
+
+            Status = $"{Entries.Count} Klassenbucheinträge anderer Lehrkräfte, " +
+                     $"{AbsenceEntries.Count} Fehlzeiten-Tage im Zeitraum.";
+            NotifyListState();
+        }
+        catch (WebUntisIntegrationException ex) { Status = ex.Message; }
+        finally { Busy = false; NotifyListState(); }
+    }
+
+    // WebUntis liefert Namen je nach Bericht in anderer Reihenfolge als der Schülerreport, aus dem
+    // StudentFilter beim Klick in der Übersicht gesetzt wird (siehe UntisNameMatching) - ein
+    // exakter String-Vergleich hier ließ die gefilterten Listen fälschlich leer erscheinen.
+    private bool MatchesStudentFilter(UntisForeignClassRegisterEventDto entry) =>
+        string.IsNullOrWhiteSpace(StudentFilter) || UntisNameMatching.NamesMatch(entry.StudentName, StudentFilter);
+
+    private bool MatchesStudentFilter(UntisClassAbsenceEntryDto entry) =>
+        string.IsNullOrWhiteSpace(StudentFilter) || UntisNameMatching.NamesMatch(entry.StudentName, StudentFilter);
+
+    private static bool TryDate(int value, out DateOnly date) =>
+        DateOnly.TryParseExact(value.ToString(), "yyyyMMdd", out date);
+
+    private void NotifyListState()
+    {
+        OnPropertyChanged(nameof(HasEntries));
+        OnPropertyChanged(nameof(HasAbsenceEntries));
+        OnPropertyChanged(nameof(HasCategoryAggregates));
+    }
+}

LehrerApp.Desktop/ViewModels/ClassTeacher/ClassTeacherOverviewViewModel.cs

@@ -0,0 +1,792 @@
+using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Desktop.Services;
+
+namespace LehrerApp.Desktop.ViewModels.ClassTeacher;
+
+/// <summary>Semantische Statusstufe einer Zeile bzw. eines Hinweises. Bewusst ohne Farbwert im
+/// ViewModel: Die Zuordnung zu einem Pinsel passiert über Style-Klassen in XAML
+/// (<c>Styles/SemanticBrushes.axaml</c>), damit ein Theme-Wechsel hell/dunkel sie live mitnimmt —
+/// ein hart codierter Hex-String aus dem ViewModel bliebe beim Wechsel unverändert stehen.</summary>
+public enum ClassTeacherStatusKind { Ok, Info, Warning, Danger }
+
+public sealed record ClassTeacherRosterRow(string StudentName, int? ExternKey, bool HasAbsenceToday,
+    string? AbsenceTooltip, bool HasRecentClassRegisterEntry)
+{
+    public ClassAbsenceDaySummaryRow? TodayAbsence { get; init; }
+    public bool HasClassRegisterToday { get; init; }
+    public bool IsLate => TodayAbsence is { } a &&
+        (a.TotalAbsentPeriods == 0 || a.AbsenceReasons.Any(IsLateReason));
+    public bool IsUnexcused => TodayAbsence?.Statuses.Any(s =>
+        s.Contains("nicht entsch", StringComparison.OrdinalIgnoreCase)) == true;
+    public bool NeedsAttention => HasAbsenceToday || HasRecentClassRegisterEntry;
+    public int AttentionRank => IsUnexcused ? 0 : IsLate ? 1 : HasAbsenceToday ? 2 :
+        HasRecentClassRegisterEntry ? 3 : 4;
+
+    public string Initials
+    {
+        get
+        {
+            var parts = StudentName.Split(' ', StringSplitOptions.RemoveEmptyEntries);
+            return string.Concat(parts.Take(2).Select(p => char.ToUpperInvariant(p[0])));
+        }
+    }
+
+    public string StatusText
+    {
+        get
+        {
+            if (TodayAbsence is null)
+                return HasRecentClassRegisterEntry ? "Neuer Klassenbucheintrag" : "Keine gemeldete Fehlzeit";
+            var core = IsLate
+                ? $"{TodayAbsence.TotalAbsentMinutes} Min. verspätet"
+                : TodayAbsence.CountsAsFullDay
+                    ? "Ganzer Fehltag"
+                    : $"{TodayAbsence.TotalAbsentPeriods} Fehlstunde{(TodayAbsence.TotalAbsentPeriods == 1 ? "" : "n")}";
+            return IsUnexcused ? $"{core} · Unentschuldigt" : core;
+        }
+    }
+
+    public ClassTeacherStatusKind StatusKind => IsUnexcused ? ClassTeacherStatusKind.Danger :
+        HasAbsenceToday ? ClassTeacherStatusKind.Warning :
+        HasRecentClassRegisterEntry ? ClassTeacherStatusKind.Info : ClassTeacherStatusKind.Ok;
+    public bool IsDangerStatus => StatusKind == ClassTeacherStatusKind.Danger;
+    public bool IsWarningStatus => StatusKind == ClassTeacherStatusKind.Warning;
+    public bool IsInfoStatus => StatusKind == ClassTeacherStatusKind.Info;
+    public string ClassRegisterLabel => HasClassRegisterToday ? "Eintrag heute" :
+        HasRecentClassRegisterEntry ? "Eintrag diese Woche" : "";
+
+    /// Quick-Win Barrierefreiheit: der Status wurde bislang ausschließlich über die Farbe des
+    /// linken Balkens/Texts transportiert. Ein kleines vorangestelltes Symbol macht Warnung/Gefahr
+    /// auch ohne verlässliche Farbunterscheidung erkennbar (und beim schnellen Scannen der Liste).
+    public string StatusTextWithGlyph => StatusKind switch
+    {
+        ClassTeacherStatusKind.Danger => $"✕ {StatusText}",
+        ClassTeacherStatusKind.Warning => $"△ {StatusText}",
+        _ => StatusText,
+    };
+
+    /// Kumulierte Fehlzeiten seit Schuljahresbeginn (Nutzer-Feedback: der Heute-Snapshot allein
+    /// sagt für Zeugnis/Attestpflicht wenig aus). <see cref="SchoolDaysElapsed"/> zählt Werktage
+    /// abzüglich der über WebUntis geladenen Ferien (<see cref="ClassTeacherOverviewViewModel.CountSchoolWeekdays"/>).
+    public int YearAbsenceDayCount { get; init; }
+    public int YearUnexcusedDayCount { get; init; }
+    public int SchoolDaysElapsed { get; init; }
+    /// Nutzer-Feedback: nachdem der Nenner zeitweise Ferientage mitzählte (siehe TODO.md), soll die
+    /// Herkunft der Zahl nachvollziehbar bleiben, ohne dafür die WebUntis-Ferienliste separat
+    /// nachschlagen zu müssen — deshalb hier sichtbar im Tooltip statt nur intern verrechnet.
+    public int HolidayWeekdaysExcluded { get; init; }
+    /// Angenommener erster Unterrichtstag (<see cref="ClassTeacherOverviewViewModel.EstimateTermStart"/>),
+    /// aus demselben Nachvollziehbarkeits-Grund wie <see cref="HolidayWeekdaysExcluded"/> im Tooltip
+    /// sichtbar — WebUntis' Ferienkalender deckt die Sommerferien selbst nicht ab (siehe TODO.md),
+    /// die Korrektur passiert also am Startpunkt, nicht an abgezogenen Tagen mittendrin.
+    public DateOnly TermStart { get; init; }
+    public bool HasYearSummary => SchoolDaysElapsed > 0 && YearAbsenceDayCount > 0;
+    public int YearAbsenceRatePercent =>
+        SchoolDaysElapsed <= 0 ? 0 : (int)Math.Round(100d * YearAbsenceDayCount / SchoolDaysElapsed);
+    public string YearSummaryLabel => HasYearSummary
+        ? $"{YearAbsenceRatePercent} % Fehlzeit seit Schuljahresbeginn" : "";
+    public string? YearSummaryTooltip => !HasYearSummary ? null :
+        $"{YearAbsenceDayCount} von {SchoolDaysElapsed} Schultagen seit {TermStart:dd.MM.} mit Fehlzeit" +
+        (YearUnexcusedDayCount > 0 ? $" · {YearUnexcusedDayCount} unentschuldigt" : "") +
+        (HolidayWeekdaysExcluded > 0 ? $" · {HolidayWeekdaysExcluded} Ferientage abgezogen" : "");
+
+    private static bool IsLateReason(string reason) =>
+        reason.Contains("verspät", StringComparison.OrdinalIgnoreCase);
+
+    public static IReadOnlyList<ClassTeacherRosterRow> Build(
+        IReadOnlyList<UntisStudentRosterCacheEntry> students,
+        IReadOnlyList<ClassAbsenceDaySummaryRow> todayAbsences,
+        IReadOnlyList<UntisForeignClassRegisterEventDto> recentClassRegisterEntries,
+        DateOnly? today = null,
+        IReadOnlyList<ClassAbsenceDaySummaryRow>? yearAbsences = null,
+        int schoolDaysElapsed = 0,
+        int holidayWeekdaysExcluded = 0,
+        DateOnly termStart = default)
+    {
+        var referenceDate = today ?? todayAbsences.FirstOrDefault()?.Date ?? DateOnly.FromDateTime(DateTime.Today);
+        var absenceByKey = todayAbsences.Where(a => a.ExternKey is not null)
+            .GroupBy(a => a.ExternKey!.Value).ToDictionary(g => g.Key, g => g.First());
+        var absenceByName = todayAbsences.GroupBy(a => UntisNameMatching.NameKey(a.StudentName))
+            .ToDictionary(g => g.Key, g => g.First());
+        var recentByName = recentClassRegisterEntries.GroupBy(e => UntisNameMatching.NameKey(e.StudentName))
+            .ToDictionary(g => g.Key, g => g.ToList());
+        var yearRows = yearAbsences ?? [];
+        var yearByKey = yearRows.Where(a => a.ExternKey is not null)
+            .GroupBy(a => a.ExternKey!.Value).ToDictionary(g => g.Key, g => g.ToList());
+        var yearByName = yearRows.GroupBy(a => UntisNameMatching.NameKey(a.StudentName))
+            .ToDictionary(g => g.Key, g => g.ToList());
+
+        return students.Select(student =>
+            {
+                var nameKey = UntisNameMatching.NameKey(student.DisplayName);
+                var absence = (student.ExternKey is { } key ? absenceByKey.GetValueOrDefault(key) : null)
+                    ?? absenceByName.GetValueOrDefault(nameKey);
+                var registerEntries = recentByName.GetValueOrDefault(nameKey) ?? [];
+                var yearEntries = (student.ExternKey is { } yearKey ? yearByKey.GetValueOrDefault(yearKey) : null)
+                    ?? yearByName.GetValueOrDefault(nameKey) ?? [];
+                return new ClassTeacherRosterRow(student.DisplayName, student.ExternKey, absence is not null,
+                    absence is null ? null : $"{absence.TotalAbsentPeriods} Stunde(n) — {absence.StatusLabel}",
+                    registerEntries.Count > 0)
+                {
+                    TodayAbsence = absence,
+                    HasClassRegisterToday = registerEntries.Any(e => TryDate(e.Date, out var date) && date == referenceDate),
+                    YearAbsenceDayCount = yearEntries.Count,
+                    YearUnexcusedDayCount = yearEntries.Count(r => r.IsUnexcused),
+                    SchoolDaysElapsed = schoolDaysElapsed,
+                    HolidayWeekdaysExcluded = holidayWeekdaysExcluded,
+                    TermStart = termStart,
+                };
+            })
+            .OrderBy(r => r.AttentionRank).ThenBy(r => r.StudentName).ToList();
+    }
+
+    private static bool TryDate(int value, out DateOnly date) =>
+        DateOnly.TryParseExact(value.ToString(), "yyyyMMdd", out date);
+}
+
+/// Ein gestapelter Tages-Balken statt drei unabhängig skalierter (Nutzer-Feedback: die vorherige
+/// Version zeigte Alerts/Unentschuldigt/Verspätet als drei separate, gleich hohe Balken, obwohl
+/// Unentschuldigt und Verspätet Teilmengen von Alerts sind — das suggerierte fälschlich drei
+/// unabhängige Größen). Die drei Segmente sind überschneidungsfrei (Unentschuldigt hat Vorrang
+/// vor Verspätet, wie bei <see cref="ClassTeacherRosterRow.AttentionRank"/>).
+public sealed record ClassTeacherTrendDay(string DayLabel, int AlertCount, int UnexcusedCount,
+    int LateExcusedCount, int ExcusedCount, double UnexcusedFraction, double LateExcusedFraction,
+    double ExcusedFraction)
+{
+    /// Anteile 0…1 des höchsten Tages der letzten 7 Schultage statt fester Pixelbreiten
+    /// (Quick-Win, Nutzer-Feedback: die Balkenbreite hing bisher an einer im ViewModel hart
+    /// codierten Pixelkonstante, die mit der tatsächlichen Breite der Seitenspalte in XAML
+    /// synchron gehalten werden musste). Die View multipliziert diese Anteile per MultiBinding
+    /// (<see cref="LehrerApp.Desktop.Converters.FractionWidthConverter"/>) mit der tatsächlich gerenderten Breite
+    /// der Track-Leiste — bleibt damit auch dann korrekt, wenn die Seitenspalte mal eine andere
+    /// Breite bekommt. <c>Grid.ColumnDefinitions</c> ließ sich dafür nicht binden (kein Setter bei
+    /// kompilierten Bindings, AVLN3000), deshalb Pixelbreite statt Grid-Sternspalten.
+    public double TotalFraction => UnexcusedFraction + LateExcusedFraction + ExcusedFraction;
+    public string DetailTooltip =>
+        $"{UnexcusedCount} unentschuldigt · {LateExcusedCount} verspätet · {ExcusedCount} entschuldigt";
+}
+public sealed record ClassTeacherPatternNotice(string StudentName, string Message,
+    ClassTeacherStatusKind Kind, bool CanCreateReminder = false)
+{
+    public bool IsDangerStatus => Kind == ClassTeacherStatusKind.Danger;
+    public bool IsWarningStatus => Kind == ClassTeacherStatusKind.Warning;
+    public bool IsInfoStatus => Kind == ClassTeacherStatusKind.Info;
+}
+
+/// <summary>Ein Fehltag, der aktuell (Stand letztem Abruf) als unentschuldigt geführt wird —
+/// Nutzer-Feedback: die Übersicht zeigte bislang nur den Heute-Snapshot und einen 7-Tage-Trend,
+/// aber keine Liste konkreter offener Fälle, die man abarbeiten könnte. Läuft über die ohnehin
+/// für die Jahresfehlquote geladenen Daten (<see cref="ClassTeacherOverviewViewModel.Load"/>),
+/// kein zusätzlicher Abruf.</summary>
+public sealed record ClassTeacherOpenExcuseRow(string StudentName, DateOnly Date, int DaysOpen)
+{
+    /// Verbreitete Regelung in vielen Bundesländern: Entschuldigung "innerhalb von drei Tagen"
+    /// nach der Fehlzeit (z.B. § 43 Abs. 2 SchulG NRW). Nur ein Richtwert für die optische
+    /// Hervorhebung hier — WebUntis liefert keine schulspezifische Frist, und die tatsächliche
+    /// Regelung kann je nach Bundesland/Schulordnung abweichen.
+    public const int DeadlineDays = 3;
+    public string DateLabel => Date.ToString("dd.MM.");
+    public bool IsOverdue => DaysOpen > DeadlineDays;
+    public string DaysOpenLabel => $"seit {DaysOpen} Tag{(DaysOpen == 1 ? "" : "en")} unentschuldigt";
+
+    public static IReadOnlyList<ClassTeacherOpenExcuseRow> Build(
+        IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDays, DateOnly today) =>
+        // Verspätungen ausgeschlossen: dafür gibt es i.d.R. keine Entschuldigungspflicht, eine
+        // "Entschuldigung fehlt"-Erinnerung wäre hier gegenstandslos. Wiederholte Verspätungen
+        // laufen stattdessen über die Mustererkennung (siehe BuildPatternNotices).
+        absenceDays.Where(a => a.IsUnexcused && !a.IsLate)
+            .Select(a => new ClassTeacherOpenExcuseRow(a.StudentDisplayName, a.Date,
+                today.DayNumber - a.Date.DayNumber))
+            .OrderByDescending(r => r.DaysOpen).ThenBy(r => r.StudentName)
+            .ToList();
+}
+
+public partial class ClassTeacherOverviewViewModel : ObservableObject
+{
+    private readonly WebUntisSettingsService _settings;
+    private readonly WebUntisIntegrationService _untis;
+    private readonly UntisReportCacheService _cache;
+    private readonly SchoolYearService _schoolYear;
+    private readonly IWorkTaskRepository _workTasks;
+    private readonly IStudentRepository _students;
+    private readonly IParticipationRepository _participation;
+    private readonly IParticipationSessionRepository _participationSessions;
+    private readonly AppLogger? _logger;
+
+    public ClassTeacherDetailsViewModel DetailsTab { get; }
+    public ObservableCollection<ClassTeacherRosterRow> Roster { get; } = [];
+    public ObservableCollection<ClassTeacherRosterRow> PrimaryRoster { get; } = [];
+    public ObservableCollection<ClassTeacherRosterRow> SecondaryRoster { get; } = [];
+    public ObservableCollection<ClassTeacherTrendDay> TrendDays { get; } = [];
+    public ObservableCollection<ClassTeacherPatternNotice> PatternNotices { get; } = [];
+    public ObservableCollection<ClassTeacherOpenExcuseRow> OpenExcuses { get; } = [];
+
+    [ObservableProperty] private string? _homeroomClassName;
+    [ObservableProperty] private int _activeTabIndex;
+    [ObservableProperty] private string _status = "";
+    [ObservableProperty] private bool _busy;
+    [ObservableProperty] private string _searchText = "";
+    [ObservableProperty] private int _selectedRosterFilter;
+    [ObservableProperty] private string _primarySectionTitle = "Heute auffällig";
+    [ObservableProperty] private string _secondarySectionTitle = "Weitere Schüler*innen";
+    [ObservableProperty] private int _studentCount;
+    [ObservableProperty] private int _todayAlertCount;
+    [ObservableProperty] private int _todayUnexcusedCount;
+    [ObservableProperty] private int _recentClassRegisterCount;
+    [ObservableProperty] private int _presentCount;
+    [ObservableProperty] private int _lateCount;
+    [ObservableProperty] private int _excusedAbsenceCount;
+    [ObservableProperty] private int _unexcusedAbsenceCount;
+    [ObservableProperty] private string _lastUpdatedLabel = "Noch nicht aktualisiert";
+    [ObservableProperty] private int _openExcuseOverflowCount;
+
+    public bool HomeroomClassConfigured => !string.IsNullOrWhiteSpace(HomeroomClassName);
+    public bool HasPrimaryRoster => PrimaryRoster.Count > 0;
+    public bool HasSecondaryRoster => SecondaryRoster.Count > 0;
+    public bool HasNoFilterResults => !Busy && PrimaryRoster.Count == 0 && SecondaryRoster.Count == 0;
+    public bool HasPatternNotices => PatternNotices.Count > 0;
+    public bool HasOpenExcuses => OpenExcuses.Count > 0;
+    public bool HasOpenExcuseOverflow => OpenExcuseOverflowCount > 0;
+    public bool AlertsFilterSelected => SelectedRosterFilter == 0;
+    public bool ClassRegisterFilterSelected => SelectedRosterFilter == 1;
+    public bool AllFilterSelected => SelectedRosterFilter == 2;
+    public int TodayUnexcusedPercent => Percent(TodayUnexcusedCount);
+    public int LatePercent => Percent(LateCount);
+    public int PresentPercent => Percent(PresentCount);
+    public int ExcusedAbsencePercent => Percent(ExcusedAbsenceCount);
+    public int UnexcusedAbsencePercent => Percent(UnexcusedAbsenceCount);
+
+    /// Quick-Win: <see cref="TodayUnexcusedPercent"/> wurde berechnet, aber nirgends gebunden —
+    /// jetzt als zweite Zeile in der "unentschuldigt"-Kennzahlkarte sichtbar.
+    public string TodayUnexcusedSummaryLabel => $"unentschuldigt · {TodayUnexcusedPercent} %";
+
+    /// Beschriftungen für den kompakten Tagesüberblick (Quick-Win: ein gestapelter 100-%-Balken
+    /// statt vier Einzelzeilen mit separater Prozentspalte — Zahl und Anteil jetzt in einer
+    /// Zeile). Die vier Kategorien sind exklusiv und summieren sich exakt zu StudentCount, siehe
+    /// die Herleitung von Present-/Late-/Excused-/UnexcusedAbsenceCount in <see cref="Load"/>.
+    public string PresentSummaryLabel => $"{PresentCount} Anwesend · {PresentPercent} %";
+    public string LateSummaryLabel => $"{LateCount} Verspätet · {LatePercent} %";
+    public string ExcusedAbsenceSummaryLabel => $"{ExcusedAbsenceCount} Entschuldigt · {ExcusedAbsencePercent} %";
+    public string UnexcusedAbsenceSummaryLabel => $"{UnexcusedAbsenceCount} Unentschuldigt · {UnexcusedAbsencePercent} %";
+    /// Anteile 0…1 für den gestapelten Tagesüberblick-Balken (View multipliziert per MultiBinding
+    /// mit der gerenderten Track-Breite, siehe <see cref="ClassTeacherTrendDay.TotalFraction"/>
+    /// für dasselbe Muster beim Trend-Chart). Die vier Kategorien sind exklusiv und summieren sich
+    /// zu 1, da StudentCount == Present + Late + ExcusedAbsence + UnexcusedAbsence.
+    public double PresentFraction => StudentCount == 0 ? 0 : (double)PresentCount / StudentCount;
+    public double LateFraction => StudentCount == 0 ? 0 : (double)LateCount / StudentCount;
+    public double ExcusedAbsenceFraction => StudentCount == 0 ? 0 : (double)ExcusedAbsenceCount / StudentCount;
+    public double UnexcusedAbsenceFraction => StudentCount == 0 ? 0 : (double)UnexcusedAbsenceCount / StudentCount;
+    public string DayOverviewTooltip => $"{PresentCount} anwesend · {LateCount} verspätet · " +
+        $"{ExcusedAbsenceCount} entschuldigt · {UnexcusedAbsenceCount} unentschuldigt";
+
+    public Func<Task>? OnNavigateToSettings { get; set; }
+    public Func<Task>? OnNavigateToWorkload { get; set; }
+
+    public ClassTeacherOverviewViewModel(WebUntisSettingsService settings, WebUntisIntegrationService untis,
+        UntisReportCacheService cache, SchoolYearService schoolYear, IWorkTaskRepository workTasks,
+        IStudentRepository students, IParticipationRepository participation,
+        IParticipationSessionRepository participationSessions, ClassTeacherDetailsViewModel detailsTab,
+        AppLogger? logger = null)
+    {
+        _settings = settings;
+        _untis = untis;
+        _cache = cache;
+        _schoolYear = schoolYear;
+        _workTasks = workTasks;
+        _students = students;
+        _participation = participation;
+        _participationSessions = participationSessions;
+        _logger = logger;
+        DetailsTab = detailsTab;
+    }
+
+    partial void OnHomeroomClassNameChanged(string? value) => OnPropertyChanged(nameof(HomeroomClassConfigured));
+    partial void OnOpenExcuseOverflowCountChanged(int value) => OnPropertyChanged(nameof(HasOpenExcuseOverflow));
+    partial void OnSearchTextChanged(string value) => ApplyRosterFilter();
+    partial void OnSelectedRosterFilterChanged(int value)
+    {
+        OnPropertyChanged(nameof(AlertsFilterSelected));
+        OnPropertyChanged(nameof(ClassRegisterFilterSelected));
+        OnPropertyChanged(nameof(AllFilterSelected));
+        ApplyRosterFilter();
+    }
+
+    [RelayCommand]
+    private async Task Load()
+    {
+        HomeroomClassName = _settings.HomeroomClassName;
+        ActiveTabIndex = 0;
+        Roster.Clear(); PrimaryRoster.Clear(); SecondaryRoster.Clear(); TrendDays.Clear(); PatternNotices.Clear();
+        OpenExcuses.Clear(); OpenExcuseOverflowCount = 0;
+        if (!HomeroomClassConfigured)
+        {
+            Status = "Noch keine Klasse ausgewählt.";
+            NotifyRosterState();
+            return;
+        }
+
+        var className = HomeroomClassName!;
+        DetailsTab.Initialize(className);
+        Busy = true;
+        NotifyRosterState();
+        try
+        {
+            var today = DateOnly.FromDateTime(DateTime.Today);
+            var sevenDayStart = today.AddDays(-6);
+            var trendDays = LastSchoolDays(today, 7);
+            // Fehlzeiten seit Schuljahresbeginn statt nur der letzten 7 Tage: liefert die
+            // Kennzahl unten (YearSummaryLabel) und den Nenner für die Fehlquote in einem Abruf.
+            // UntisReportCacheService cached diesen "kalten" Bereich dauerhaft (siehe dort) —
+            // teuer ist nur der erste Abruf pro Schuljahr, nicht jedes Öffnen der Ansicht.
+            var yearStart = _schoolYear.SchoolYearStart(_schoolYear.CurrentSchoolYear(today));
+            var studentsTask = _cache.GetStudentRosterAsync(className);
+            var absencesTask = _cache.GetAbsencesAsync(className, yearStart, today);
+            var classRegisterTask = _cache.GetClassRegisterEventsAsync(className, sevenDayStart, today);
+            var holidaysTask = GetHolidaysAsync();
+            await Task.WhenAll(studentsTask, absencesTask, classRegisterTask, holidaysTask);
+
+            var absenceDaysYear = ClassAbsenceDaySummaryRow.GroupByStudentAndDay(absencesTask.Result);
+            var todayAbsences = absenceDaysYear.Where(a => a.Date == today).ToList();
+            var termStart = EstimateTermStart(absenceDaysYear, yearStart);
+            var rawWeekdaysElapsed = CountSchoolWeekdays(termStart, today, []);
+            var schoolDaysElapsed = CountSchoolWeekdays(termStart, today, holidaysTask.Result);
+            var holidayWeekdaysExcluded = rawWeekdaysElapsed - schoolDaysElapsed;
+            foreach (var row in ClassTeacherRosterRow.Build(studentsTask.Result, todayAbsences,
+                         classRegisterTask.Result, today, absenceDaysYear, schoolDaysElapsed,
+                         holidayWeekdaysExcluded, termStart)) Roster.Add(row);
+
+            StudentCount = Roster.Count;
+            TodayAlertCount = Roster.Count(r => r.HasAbsenceToday);
+            TodayUnexcusedCount = Roster.Count(r => r.IsUnexcused);
+            LateCount = Roster.Count(r => r.IsLate);
+            PresentCount = Roster.Count(r => !r.HasAbsenceToday);
+            ExcusedAbsenceCount = Roster.Count(r => r.HasAbsenceToday && !r.IsLate && !r.IsUnexcused);
+            UnexcusedAbsenceCount = Roster.Count(r => r.HasAbsenceToday && !r.IsLate && r.IsUnexcused);
+            RecentClassRegisterCount = classRegisterTask.Result.Count;
+            BuildTrend(absenceDaysYear, trendDays);
+            BuildPatternNotices(absenceDaysYear, sevenDayStart);
+            BuildWeekdayPatternNotices(absenceDaysYear);
+            BuildAttendanceParticipationNotices();
+            BuildOpenExcuses(absenceDaysYear, today);
+            LastUpdatedLabel = $"Zuletzt aktualisiert: Heute, {DateTime.Now:HH:mm}";
+            Status = $"{StudentCount} Schüler*innen · {TodayAlertCount} heute auffällig";
+            ApplyRosterFilter();
+            NotifySummary();
+        }
+        catch (WebUntisIntegrationException ex) { Status = ex.Message; NotifyRosterState(); }
+        finally { Busy = false; NotifyRosterState(); }
+    }
+
+    [RelayCommand] private void ShowAlerts() => SelectedRosterFilter = 0;
+    [RelayCommand] private void ShowClassRegister() => SelectedRosterFilter = 1;
+    [RelayCommand] private void ShowAll() => SelectedRosterFilter = 2;
+
+    [RelayCommand]
+    private void OpenClassRegister()
+    {
+        DetailsTab.StudentFilter = "";
+        ActiveTabIndex = 1;
+        DetailsTab.LoadCommand.Execute(null);
+    }
+
+    [RelayCommand]
+    private void OpenAbsences()
+    {
+        DetailsTab.StudentFilter = "";
+        ActiveTabIndex = 2;
+        DetailsTab.LoadCommand.Execute(null);
+    }
+
+    [RelayCommand]
+    private void ShowDetailsForStudent(ClassTeacherRosterRow? row)
+    {
+        if (row is null) return;
+        DetailsTab.StudentFilter = row.StudentName;
+        ActiveTabIndex = row.HasAbsenceToday ? 2 : 1;
+        DetailsTab.LoadCommand.Execute(null);
+    }
+
+    [RelayCommand] private async Task GoToSettings()
+    { if (OnNavigateToSettings is not null) await OnNavigateToSettings(); }
+
+    [RelayCommand] private async Task GoToWorkload()
+    { if (OnNavigateToWorkload is not null) await OnNavigateToWorkload(); }
+
+    private void ApplyRosterFilter()
+    {
+        PrimaryRoster.Clear(); SecondaryRoster.Clear();
+        var query = Roster.Where(r => string.IsNullOrWhiteSpace(SearchText) ||
+            r.StudentName.Contains(SearchText.Trim(), StringComparison.CurrentCultureIgnoreCase));
+        if (SelectedRosterFilter == 0)
+        {
+            PrimarySectionTitle = "Heute auffällig";
+            foreach (var row in query.Where(r => r.HasAbsenceToday)) PrimaryRoster.Add(row);
+        }
+        else if (SelectedRosterFilter == 1)
+        {
+            PrimarySectionTitle = "Klassenbucheinträge der letzten 7 Tage";
+            foreach (var row in query.Where(r => r.HasRecentClassRegisterEntry)) PrimaryRoster.Add(row);
+        }
+        else
+        {
+            PrimarySectionTitle = "Heute auffällig";
+            SecondarySectionTitle = "Weitere Schüler*innen";
+            foreach (var row in query.Where(r => r.NeedsAttention)) PrimaryRoster.Add(row);
+            foreach (var row in query.Where(r => !r.NeedsAttention)) SecondaryRoster.Add(row);
+        }
+        NotifyRosterState();
+    }
+
+    /// Letzte <paramref name="days"/> statt letzte 7 Kalendertage (Nutzer-Feedback: an zwei von
+    /// sieben Tagen war der Trend bislang systematisch leer, weil Wochenenden mitzählten). Ohne
+    /// Ferienkalender — siehe <see cref="LastSchoolDays"/>.
+    private void BuildTrend(IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDays, IReadOnlyList<DateOnly> days)
+    {
+        var today = days[^1];
+        var counts = days.Select(date =>
+        {
+            var rows = absenceDays.Where(r => r.Date == date).ToList();
+            var unexcused = rows.Count(r => r.IsUnexcused);
+            var lateExcused = rows.Count(r => !r.IsUnexcused && r.IsLate);
+            var excused = rows.Count(r => !r.IsUnexcused && !r.IsLate);
+            return (Date: date, Unexcused: unexcused, LateExcused: lateExcused, Excused: excused,
+                Total: unexcused + lateExcused + excused);
+        }).ToList();
+        var max = Math.Max(1, counts.Max(c => c.Total));
+        foreach (var day in counts)
+            TrendDays.Add(new ClassTeacherTrendDay(day.Date == today ? "Heute" : day.Date.ToString("ddd"),
+                day.Total, day.Unexcused, day.LateExcused, day.Excused,
+                (double)day.Unexcused / max, (double)day.LateExcused / max, (double)day.Excused / max));
+    }
+
+    /// Letzte <paramref name="count"/> Werktage bis einschließlich <paramref name="end"/>, ohne
+    /// Ferienkalender (bewusste Vereinfachung, siehe TODO.md 12.4-Nachtrag) — die App kennt keine
+    /// Schulferien, nur Wochenenden.
+    private static IReadOnlyList<DateOnly> LastSchoolDays(DateOnly end, int count)
+    {
+        var days = new List<DateOnly>();
+        for (var cursor = end; days.Count < count; cursor = cursor.AddDays(-1))
+            if (cursor.DayOfWeek is not (DayOfWeek.Saturday or DayOfWeek.Sunday))
+                days.Add(cursor);
+        days.Reverse();
+        return days;
+    }
+
+    /// Nutzer-Feedback: Schüler*innen, die seit Unterrichtsbeginn nachweislich an jedem Tag
+    /// fehlten, zeigten trotzdem nur ~57 % Fehlquote statt der erwarteten ~100 %. Ursache: der
+    /// Nenner zählte bislang jeden Werktag ab dem fest verdrahteten 1. August
+    /// (<see cref="SchoolYearService.SchoolYearStart"/>) als "Schultag" mit — die Sommerferien
+    /// enden je nach Bundesland/Jahr aber erst Wochen später, und genau zu Schuljahresbeginn macht
+    /// diese Ferienzeit einen großen Teil des bis dahin "verstrichenen" Zeitraums aus. WebUntis
+    /// kennt einen Teil des echten Ferienkalenders (<c>getHolidays</c>-Bericht, hier zwischen den
+    /// Werktagen ausgeschlossen) und behebt damit die kleineren Verzerrungen durch Herbst-/
+    /// Weihnachts-/Osterferien im weiteren Jahresverlauf. Die Sommerferien selbst liefert
+    /// <c>getHolidays</c> nach Prüfung der echten Antwort für dieses Konto aber NIE (über 11 Jahre
+    /// zurück kein einziger Sommerferien-Eintrag, siehe <see cref="EstimateTermStart"/>) — sie
+    /// liegen WebUntis-intern vermutlich außerhalb jedes Schuljahres-Datensatzes (der bei 1.8./31.7.
+    /// endet), nicht "in" einem davon. Für die Sommerferien bleibt deshalb weiterhin
+    /// <see cref="EstimateTermStart"/> nötig, das den Startpunkt selbst korrigiert statt Tage
+    /// innerhalb des Zeitraums abzuziehen.
+    public static int CountSchoolWeekdays(DateOnly start, DateOnly end, IReadOnlyList<CachedUntisHoliday> holidays)
+    {
+        if (end < start) return 0;
+        var count = 0;
+        for (var d = start; d <= end; d = d.AddDays(1))
+            if (d.DayOfWeek is not (DayOfWeek.Saturday or DayOfWeek.Sunday) &&
+                !holidays.Any(h => d >= h.Start && d <= h.End))
+                count++;
+        return count;
+    }
+
+    /// Ergänzt <see cref="CountSchoolWeekdays"/> um genau die Lücke, die WebUntis' echter
+    /// Ferienkalender nicht schließt: die Sommerferien. Nimmt den frühesten Tag mit irgendeinem
+    /// Fehlzeiten-Eintrag der ganzen Klasse als Näherung für den tatsächlichen ersten
+    /// Unterrichtstag (ein solcher Eintrag kann nur an einem Tag mit tatsächlich stattfindendem
+    /// Unterricht entstehen) — Rückfall auf <paramref name="fallback"/>, wenn noch keine
+    /// Fehlzeiten vorliegen (dann bleibt <see cref="ClassTeacherRosterRow.HasYearSummary"/>
+    /// ohnehin ausgeblendet).
+    public static DateOnly EstimateTermStart(IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDaysYear, DateOnly fallback) =>
+        absenceDaysYear.Count > 0 ? absenceDaysYear.Min(a => a.Date) : fallback;
+
+    /// Ferien ändern sich innerhalb eines Schuljahrs praktisch nie (anders als die
+    /// Fehlzeiten-/Klassenbuchberichte, deshalb hier keine der stündlichen "heißes Fenster"-Logik
+    /// aus <see cref="UntisReportCacheService"/>, sondern ein einfacher tagesgenauer Cache über
+    /// <see cref="WebUntisSettingsService"/> — kein zusätzliches LiteDB-Repository nötig). Schlägt
+    /// der Live-Abruf fehl (z. B. kurzzeitig kein Netz), wird der zuletzt bekannte Stand
+    /// weiterverwendet statt die ganze Übersicht mit einem Fehler zu blockieren; ist noch nie
+    /// erfolgreich abgerufen worden, bleibt die Liste leer und <see cref="CountSchoolWeekdays"/>
+    /// verhält sich wie vorher (reine Werktagszählung ohne Ferienabzug).
+    private static readonly TimeSpan HolidaysRefreshInterval = TimeSpan.FromDays(1);
+
+    private async Task<IReadOnlyList<CachedUntisHoliday>> GetHolidaysAsync()
+    {
+        var cached = _settings.GetCachedHolidays();
+        if (cached is not null && _settings.HolidaysFetchedAt is { } fetchedAt &&
+            DateTime.UtcNow - fetchedAt < HolidaysRefreshInterval)
+            return cached;
+        try
+        {
+            var fresh = (await _untis.GetHolidaysAsync())
+                .Select(h => new CachedUntisHoliday(h.Name, ParseDate(h.StartDate), ParseDate(h.EndDate)))
+                .ToList();
+            _settings.SetCachedHolidays(fresh, DateTime.UtcNow);
+            _logger?.Info("Klassenlehrer: WebUntis-Ferien geladen — " +
+                string.Join("; ", fresh.Select(h => $"{h.Name} {h.Start:yyyy-MM-dd}..{h.End:yyyy-MM-dd}")));
+            return fresh;
+        }
+        catch (WebUntisIntegrationException ex)
+        {
+            _logger?.Error("Klassenlehrer: WebUntis-Ferienabruf fehlgeschlagen", ex);
+            return cached ?? [];
+        }
+    }
+
+    private static DateOnly ParseDate(int value) => DateOnly.ParseExact(value.ToString(), "yyyyMMdd");
+
+    private const int LateYearEscalationThreshold = 5;
+
+    private void BuildPatternNotices(IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDaysYear, DateOnly sevenDayStart)
+    {
+        var displayNames = Roster.GroupBy(r => UntisNameMatching.NameKey(r.StudentName))
+            .ToDictionary(g => g.Key, g => g.First().StudentName);
+        foreach (var notice in DetectLatePatterns(absenceDaysYear, displayNames, sevenDayStart))
+            PatternNotices.Add(notice);
+        OnPropertyChanged(nameof(HasPatternNotices));
+    }
+
+    /// Verspätungen sind i.d.R. nicht entschuldigungsfähig (siehe <see cref="ClassTeacherOpenExcuseRow.Build"/>)
+    /// — eine Häufung ist trotzdem ein Signal, nur eines für ein Elterngespräch/einen Brief statt
+    /// für eine fehlende Entschuldigung. Zwei Stufen, Nutzer-Feedback: ein kurzfristiges Cluster
+    /// (<paramref name="sevenDayStart"/>..heute) bleibt ein sanfter Hinweis ohne Aktion, eine hohe
+    /// Jahressumme eskaliert zu Danger mit Wiedervorlage-Option
+    /// (<see cref="CreateReminderForPatternNoticeCommand"/>). Reine, ohne ViewModel-Zustand
+    /// testbare Kernlogik (gleiches Muster wie <see cref="DetectWeekdayPatterns"/>).
+    public static IReadOnlyList<ClassTeacherPatternNotice> DetectLatePatterns(
+        IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDaysYear,
+        IReadOnlyDictionary<string, string> displayNamesByKey,
+        DateOnly sevenDayStart,
+        int lateYearEscalationThreshold = LateYearEscalationThreshold)
+    {
+        var notices = new List<ClassTeacherPatternNotice>();
+        foreach (var group in absenceDaysYear.GroupBy(row => UntisNameMatching.NameKey(row.StudentName)))
+        {
+            var rows = group.ToList();
+            var displayName = displayNamesByKey.GetValueOrDefault(group.Key) ?? rows[0].StudentDisplayName;
+            var weekRows = rows.Where(row => row.Date >= sevenDayStart).ToList();
+            var lateDaysWeek = weekRows.Count(row => row.IsLate);
+            var unexcusedDaysWeek = weekRows.Count(row => row.IsUnexcused && !row.IsLate);
+            var lateDaysYear = rows.Count(row => row.IsLate);
+
+            if (unexcusedDaysWeek >= 2)
+                notices.Add(new ClassTeacherPatternNotice(displayName,
+                    $"{unexcusedDaysWeek} unentschuldigte Fehltage in 7 Tagen", ClassTeacherStatusKind.Danger));
+            else if (lateDaysYear >= lateYearEscalationThreshold)
+                notices.Add(new ClassTeacherPatternNotice(displayName,
+                    $"{lateDaysYear} Verspätungen seit Schuljahresbeginn – Elterngespräch oder Brief erwägen",
+                    ClassTeacherStatusKind.Danger, CanCreateReminder: true));
+            else if (lateDaysWeek >= 2)
+                notices.Add(new ClassTeacherPatternNotice(displayName,
+                    $"{lateDaysWeek}-mal verspätet in 7 Tagen", ClassTeacherStatusKind.Warning));
+        }
+        return notices;
+    }
+
+    /// Erweiterte Mustererkennung (Nutzer-Feedback): die obigen Regeln schauen nur auf die letzten
+    /// 7 Tage und nur auf unentschuldigt/verspätet. Ein Wochentags-Schwerpunkt über einen längeren
+    /// Zeitraum (z.B. "immer montags") ist ein eigenes, oft erst über mehrere Wochen sichtbares
+    /// Signal — deshalb mit den seit Schuljahresbeginn geladenen Daten, nicht nur den letzten 7
+    /// Tagen. Wer schon eine Notiz aus <see cref="BuildPatternNotices"/> hat, wird hier
+    /// ausgelassen, damit die Liste nicht zwei Hinweise für dieselbe Person zeigt.
+    private void BuildWeekdayPatternNotices(IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDays)
+    {
+        var displayNames = Roster.GroupBy(r => UntisNameMatching.NameKey(r.StudentName))
+            .ToDictionary(g => g.Key, g => g.First().StudentName);
+        var alreadyNoted = PatternNotices.Select(n => n.StudentName).ToHashSet();
+        foreach (var notice in DetectWeekdayPatterns(absenceDays, displayNames, alreadyNoted))
+            PatternNotices.Add(notice);
+        OnPropertyChanged(nameof(HasPatternNotices));
+    }
+
+    /// Reine, ohne ViewModel-Zustand testbare Kernlogik (gleiches Muster wie
+    /// <see cref="ClassTeacherRosterRow.Build"/>). <paramref name="minSampleSize"/> verhindert,
+    /// dass zwei zufällig auf denselben Wochentag fallende Fehltage schon als "Muster" gelten;
+    /// <paramref name="clusterThreshold"/> verlangt eine deutliche Häufung, nicht nur eine leichte
+    /// Mehrheit.
+    public static IReadOnlyList<ClassTeacherPatternNotice> DetectWeekdayPatterns(
+        IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDays,
+        IReadOnlyDictionary<string, string> displayNamesByKey,
+        ISet<string> excludeDisplayNames,
+        int minSampleSize = 3, double clusterThreshold = 0.6)
+    {
+        var notices = new List<ClassTeacherPatternNotice>();
+        foreach (var group in absenceDays.GroupBy(row => UntisNameMatching.NameKey(row.StudentName)))
+        {
+            var rows = group.ToList();
+            if (rows.Count < minSampleSize) continue;
+            var displayName = displayNamesByKey.GetValueOrDefault(group.Key) ?? rows[0].StudentDisplayName;
+            if (excludeDisplayNames.Contains(displayName)) continue;
+
+            var top = rows.GroupBy(r => r.Date.DayOfWeek)
+                .Select(g => (Day: g.Key, Count: g.Count()))
+                .OrderByDescending(g => g.Count).First();
+            if ((double)top.Count / rows.Count < clusterThreshold) continue;
+
+            notices.Add(new ClassTeacherPatternNotice(displayName,
+                $"{top.Count} von {rows.Count} Fehltagen an einem {WeekdayLabel(top.Day)}",
+                ClassTeacherStatusKind.Info));
+        }
+        return notices;
+    }
+
+    /// Nutzer-Feedback: "Hohe Fehlquote bei gleichzeitig fallender Mitarbeit ist ein Signal, das
+    /// WebUntis allein nicht liefert." Verknüpft die ohnehin geladene Jahresfehlquote
+    /// (<see cref="ClassTeacherRosterRow.YearAbsenceRatePercent"/>) mit dem Mitarbeit-Trend aus
+    /// dem Dokumentations-/Mitarbeitsmodul (<see cref="IParticipationRepository"/>, gruppen-
+    /// übergreifend über <c>GetByStudent</c>, gleiches Muster wie die Fehlzeitenbilanz in
+    /// StudentDetailViewModel). Bewusst zurückhaltend: nur bei bereits spürbar erhöhter Fehlquote
+    /// UND eindeutig fallendem Trend (erste vs. zweite Hälfte der letzten Bewertungen, gleiche
+    /// simple Heuristik wie <c>ParticipationGradeRow.ComputeTrend</c>), sonst würde die Liste bei
+    /// jeder kleinen Schwankung anschlagen. Reine Beobachtung, keine Kausalitätsaussage — deshalb
+    /// als neutraler Hinweis (Info), nicht als Warnung/Gefahr. Die WebUntis-Rohbewertungen werden
+    /// hier bewusst NICHT nach Aspekt-Gewichtung normiert (anders als in ParticipationGradeRow):
+    /// die Aspekt-Definitionen sind je Lerngruppe konfigurierbar, der Klassenlehrer-Bereich kennt
+    /// aber keine einzelne Gruppe — ein einfacher Rohwert-Durchschnitt über alle Bewertungen ist
+    /// hier die pragmatischere Näherung als ein Konfigurations-Mismatch zu riskieren.
+    private const int CorrelationAbsenceRateThreshold = 15;
+    private void BuildAttendanceParticipationNotices()
+    {
+        var students = _students.GetAll();
+        foreach (var row in Roster.Where(r => r.HasYearSummary &&
+                     r.YearAbsenceRatePercent >= CorrelationAbsenceRateThreshold))
+        {
+            if (PatternNotices.Any(n => n.StudentName == row.StudentName)) continue;
+            var student = MatchStudent(row.StudentName, students);
+            if (student is null) continue;
+
+            var points = _participation.GetByStudent(student.Id)
+                .Select(e => (Session: _participationSessions.GetById(e.SessionId), Entry: e))
+                .Where(x => x.Session is not null && x.Entry.Ratings.Count > 0)
+                .OrderBy(x => x.Session!.Date)
+                .TakeLast(8)
+                .Select(x => x.Entry.Ratings.Average(r => r.Value))
+                .ToList();
+            if (points.Count < 4) continue;
+
+            var mid = points.Count / 2;
+            var diff = points.Skip(mid).Average() - points.Take(mid).Average();
+            if (diff <= -0.4)
+                PatternNotices.Add(new ClassTeacherPatternNotice(row.StudentName,
+                    $"{row.YearAbsenceRatePercent} % Fehlzeit seit Schuljahresbeginn, dabei zuletzt sinkende Mitarbeit",
+                    ClassTeacherStatusKind.Info));
+        }
+        OnPropertyChanged(nameof(HasPatternNotices));
+    }
+
+    /// Reine, ohne Repository-Zugriff testbare Zuordnungslogik. Nutzt <c>FirstName</c>/<c>LastName</c>
+    /// statt <see cref="Student.FullName"/>, weil dessen "Nachname, Vorname"-Format mit Komma den
+    /// leerzeichenbasierten Wortabgleich in <see cref="UntisNameMatching"/> verfälschen würde
+    /// ("Müller," bliebe ein eigenes Wort statt mit "Müller" aus dem WebUntis-Namen zu matchen).
+    public static Student? MatchStudent(string webUntisDisplayName, IReadOnlyList<Student> students)
+    {
+        var key = UntisNameMatching.NameKey(webUntisDisplayName);
+        return students.FirstOrDefault(s => UntisNameMatching.NameKey($"{s.FirstName} {s.LastName}") == key);
+    }
+
+    private static string WeekdayLabel(DayOfWeek day) => day switch
+    {
+        DayOfWeek.Monday => "Montag",
+        DayOfWeek.Tuesday => "Dienstag",
+        DayOfWeek.Wednesday => "Mittwoch",
+        DayOfWeek.Thursday => "Donnerstag",
+        DayOfWeek.Friday => "Freitag",
+        DayOfWeek.Saturday => "Samstag",
+        _ => "Sonntag",
+    };
+
+    /// Zeigt höchstens <see cref="OpenExcuseDisplayLimit"/> Zeilen — Nutzer-Feedback zu den
+    /// anderen Seitenpanels: eine lange Liste soll nicht die ganze Spalte einnehmen. Der Rest
+    /// zählt in <see cref="OpenExcuseOverflowCount"/> und wird als "+N weitere" angezeigt.
+    private const int OpenExcuseDisplayLimit = 6;
+
+    private void BuildOpenExcuses(IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDays, DateOnly today)
+    {
+        var all = ClassTeacherOpenExcuseRow.Build(absenceDays, today);
+        foreach (var row in all.Take(OpenExcuseDisplayLimit)) OpenExcuses.Add(row);
+        OpenExcuseOverflowCount = Math.Max(0, all.Count - OpenExcuseDisplayLimit);
+    }
+
+    [RelayCommand]
+    private void ShowDetailsForOpenExcuse(ClassTeacherOpenExcuseRow? row)
+    {
+        if (row is null) return;
+        DetailsTab.StudentFilter = row.StudentName;
+        ActiveTabIndex = 2;
+        DetailsTab.LoadCommand.Execute(null);
+    }
+
+    /// Nutzer-Feedback: "Aufgaben & Wiedervorlagen öffnen" führt nur ins Modul, das eigentliche
+    /// Erstellen ("Eltern anrufen – Ada Müller") musste man dort noch einmal von Hand eintippen.
+    /// Legt direkt eine Wiedervorlage an (Kind=Reminder, wie 6.1.1) statt einen Dialog zu öffnen —
+    /// der bearbeitet sie bei Bedarf im Aufgaben-Modul weiter, wo `OnEditTask` (siehe
+    /// WorkTaskListView) ohnehin nur dort verdrahtet ist. Bewusst ohne GroupId: Klassenlehrer ist
+    /// man für die ganze Klasse, nicht für einen einzelnen Kurs (siehe Klassendoku oben).
+    [RelayCommand]
+    private void CreateReminderForStudent(ClassTeacherRosterRow? row)
+    {
+        if (row is null) return;
+        SaveReminder(row.StudentName, row.StatusText, urgent: row.IsUnexcused);
+    }
+
+    [RelayCommand]
+    private void CreateReminderForOpenExcuse(ClassTeacherOpenExcuseRow? row)
+    {
+        if (row is null) return;
+        SaveReminder(row.StudentName, $"{row.DaysOpenLabel} (Fehltag vom {row.DateLabel}).",
+            urgent: row.IsOverdue);
+    }
+
+    [RelayCommand]
+    private void CreateReminderForPatternNotice(ClassTeacherPatternNotice? notice)
+    {
+        if (notice is null || !notice.CanCreateReminder) return;
+        SaveReminder(notice.StudentName, notice.Message, urgent: true);
+    }
+
+    private void SaveReminder(string studentName, string notes, bool urgent)
+    {
+        var task = new WorkTask
+        {
+            Title = $"Eltern kontaktieren – {studentName}",
+            Notes = notes,
+            Kind = TaskKind.Reminder,
+            Priority = urgent ? TaskPriority.High : TaskPriority.Normal,
+            DueDate = DateOnly.FromDateTime(DateTime.Today).AddDays(1),
+        };
+        _workTasks.Save(task);
+        Status = $"Wiedervorlage „{task.Title}\" angelegt — zu finden unter Aufgaben & Wiedervorlagen.";
+    }
+
+    private int Percent(int value) => StudentCount == 0 ? 0 : (int)Math.Round(100d * value / StudentCount);
+    private void NotifySummary()
+    {
+        OnPropertyChanged(nameof(TodayUnexcusedPercent)); OnPropertyChanged(nameof(LatePercent));
+        OnPropertyChanged(nameof(PresentPercent)); OnPropertyChanged(nameof(ExcusedAbsencePercent));
+        OnPropertyChanged(nameof(UnexcusedAbsencePercent));
+        OnPropertyChanged(nameof(TodayUnexcusedSummaryLabel));
+        OnPropertyChanged(nameof(PresentSummaryLabel)); OnPropertyChanged(nameof(LateSummaryLabel));
+        OnPropertyChanged(nameof(ExcusedAbsenceSummaryLabel)); OnPropertyChanged(nameof(UnexcusedAbsenceSummaryLabel));
+        OnPropertyChanged(nameof(PresentFraction)); OnPropertyChanged(nameof(LateFraction));
+        OnPropertyChanged(nameof(ExcusedAbsenceFraction)); OnPropertyChanged(nameof(UnexcusedAbsenceFraction));
+        OnPropertyChanged(nameof(DayOverviewTooltip));
+    }
+    private void NotifyRosterState()
+    {
+        OnPropertyChanged(nameof(HasPrimaryRoster)); OnPropertyChanged(nameof(HasSecondaryRoster));
+        OnPropertyChanged(nameof(HasNoFilterResults)); OnPropertyChanged(nameof(HasOpenExcuses));
+    }
+}

LehrerApp.Desktop/ViewModels/ClassTeacher/UntisNameMatching.cs

@@ -0,0 +1,22 @@
+namespace LehrerApp.Desktop.ViewModels.ClassTeacher;
+
+/// <summary>
+/// WebUntis liefert Schülernamen je nach Bericht in unterschiedlicher Reihenfolge — der
+/// Schülerreport baut "Vorname Nachname" (<see cref="Services.UntisStudentDto.DisplayName"/>),
+/// die Fehlzeiten-/Klassenbuchberichte liefern typischerweise "Nachname Vorname". Ein exakter
+/// String-Vergleich zwischen diesen Quellen schlägt deshalb praktisch immer fehl (Bug: gefilterte
+/// Listen im Klassenlehrer-Bereich blieben leer, Roster-Symbole waren durchgängig falsch). Der
+/// Vergleich hier ist deshalb reihenfolge-unabhängig: beide Namen werden in Wörter zerlegt und als
+/// sortierte Menge verglichen (kein Abgleich über eine externe Schülerkennung möglich, da der
+/// Klassenbuch-Bericht keine liefert, siehe UntisForeignClassRegisterEventDto).
+/// </summary>
+public static class UntisNameMatching
+{
+    public static bool NamesMatch(string? a, string? b) =>
+        !string.IsNullOrWhiteSpace(a) && !string.IsNullOrWhiteSpace(b) && NameKey(a) == NameKey(b);
+
+    public static string NameKey(string value) => string.Join(' ',
+        value.Split(' ', StringSplitOptions.RemoveEmptyEntries)
+            .Select(w => w.Trim().ToLowerInvariant())
+            .OrderBy(w => w, StringComparer.Ordinal));
+}

LehrerApp.Desktop/ViewModels/DashboardViewModel.cs

@@ -35,6 +35,7 @@ public partial class DashboardViewModel : ObservableObject
     private readonly PublicHolidayService _publicHolidays;
     private readonly SchoolCalendarSettingsService _calendarSettings;
     private readonly ISubstitutionEntryRepository _substitutions;
+    private readonly ITimeEntryRepository _timeEntries;
     private readonly IAnnualPlanEventRepository? _annualPlanEvents;
     private readonly SchoolWeatherService? _schoolWeather;
 
@@ -50,12 +51,29 @@ public partial class DashboardViewModel : ObservableObject
     /// hat rein rechnerisch schon 100 %, das ist noch kein auffälliges Muster, nur eine zu kleine
     /// Stichprobe. Dieselbe Konstante wie GroupOverviewViewModel.AttendanceMinSampleSize.
     private const int AttendanceMinSampleSize = 8;
+    /// Nutzer-Feedback: "ich vergesse es, und fasse die App auch außerhalb der Schule manchmal
+    /// nicht mehr an" — die Erinnerung an fehlende Unterrichtszeit-Erfassung schaut deshalb nicht
+    /// nur auf heute zurück, sondern auf ein paar Tage, damit ein vergessener Tag nicht verloren
+    /// geht, sobald der nächste Schultag anbricht.
+    private const int MissingTeachingTimeLookbackDays = 14;
+    /// Für den heutigen Tag soll die Erinnerung nicht schon mitten im Unterricht auftauchen —
+    /// erst diese Zeitspanne nach dem laut Stundenplan letzten Unterrichtsende.
+    private const int MissingTeachingTimeTodayDelayMinutes = 30;
+    /// Gleiche Puffer-Idee wie TimeTrackingViewModel.ComputeTodaysTeachingWindow (bewusst hier
+    /// noch einmal definiert statt geteilt — der Vorschlag ist nur zwei Zeilen Rechnung).
+    private const int TeachingWindowBufferBeforeMinutes = 15;
+    private const int TeachingWindowBufferAfterMinutes = 10;
+    /// Vorausschau für die Klausurwochen-Karte (Nutzer-Feedback): weit genug, um eine sich
+    /// anbahnende Häufung noch rechtzeitig vor dem Anlegen weiterer Klausuren zu zeigen, aber
+    /// keine Vorschau auf das ganze Schuljahr.
+    private const int ExamLoadLookaheadDays = 60;
 
     [ObservableProperty] private string _greeting = "";
     [ObservableProperty] private string _currentDate = "";
     [ObservableProperty] private string _currentSchoolYear = "";
     [ObservableProperty] private DateOnly _calendarMonth = FirstOfMonth(DateTime.Today);
     [ObservableProperty] private string _selectedDayLabel = "";
+    [ObservableProperty] private DateOnly _selectedCalendarDate = DateOnly.FromDateTime(DateTime.Today);
     [ObservableProperty] private bool _isDashboardSettingsOpen;
     [ObservableProperty] private bool _isWeatherPanelVisible;
     [ObservableProperty] private string _weatherSummary = "";
@@ -71,6 +89,8 @@ public partial class DashboardViewModel : ObservableObject
     public ObservableCollection<CalendarDayCell> CalendarDays { get; } = [];
     public ObservableCollection<OpenExcuseItem> OpenExcuses { get; } = [];
     public ObservableCollection<AttendanceWarningItem> AttendanceWarnings { get; } = [];
+    public ObservableCollection<ExamWeekLoadItem> ExamWeekLoads { get; } = [];
+    public ObservableCollection<MissingTeachingTimeItem> MissingTeachingTimeEntries { get; } = [];
     public ObservableCollection<SupportPlanDueItem> SupportPlanReviews { get; } = [];
     public ObservableCollection<UpcomingDateItem> UpcomingDates { get; } = [];
     public ObservableCollection<CorrectionProgressItem> OpenCorrections { get; } = [];
@@ -95,6 +115,10 @@ public partial class DashboardViewModel : ObservableObject
     // Sprungziel für eine ungeplante Stunde — führt direkt in den Verlaufsplan-Tab der Gruppe
     // (nicht den Standard-Tab von OnNavigateToGroup), damit das Thema gleich ergänzt werden kann.
     public Action<Guid>? OnNavigateToUnplannedLesson { get; set; }
+    // Öffnet den Nacherfassen-Dialog für einen Tag mit fehlender Unterrichtszeit-Erfassung
+    // (Nutzer-Feedback), vorbelegt mit Datum, Kategorie "Unterricht" und dem laut Stundenplan
+    // berechneten Zeitfenster — echtes Speichern bleibt eine bewusste Bestätigung im Dialog.
+    public Func<MissingTeachingTimeItem, Task>? OnAddMissingTeachingTime { get; set; }
 
     public DashboardCardOption TodayCard => Card("today");
     public DashboardCardOption TasksCard => Card("tasks");
@@ -105,8 +129,19 @@ public partial class DashboardViewModel : ObservableObject
     public DashboardCardOption UnplannedCard => Card("unplanned");
     public DashboardCardOption AlertsCard => Card("alerts");
     public DashboardCardOption AttendanceCard => Card("attendance");
+    public DashboardCardOption ExamLoadCard => Card("examload");
+    public DashboardCardOption MissingTeachingTimeCard => Card("missingteachingtime");
     public DashboardCardOption SupportCard => Card("support");
     public DashboardCardOption GroupsCard => Card("groups");
+    public int TodayLessonCount => TodaysLessons.Count;
+    public int OpenTaskCount => OpenTasks.Count;
+    public int UpcomingCount => UpcomingDates.Count;
+    public int AttentionCount => OpenExcuses.Count + AttendanceWarnings.Count + SupportPlanReviews.Count
+        + OpenCorrections.Count + UnplannedLessons.Count + Alerts.Count;
+    public string TodayLessonSummary => TodayLessonCount == 1 ? "1 Stunde" : $"{TodayLessonCount} Stunden";
+    public string OpenTaskSummary => OpenTaskCount == 1 ? "1 Aufgabe" : $"{OpenTaskCount} Aufgaben";
+    public string AttentionSummary => AttentionCount == 1 ? "1 offener Punkt" : $"{AttentionCount} offene Punkte";
+    public string UpcomingSummary => UpcomingCount == 1 ? "1 Termin" : $"{UpcomingCount} Termine";
 
     public DashboardViewModel(IGroupRepository groups, ISubjectRepository subjects, ILessonRepository lessons,
         IExamRepository exams, IExamResultRepository examResults, IGradeRepository grades,
@@ -117,7 +152,8 @@ public partial class DashboardViewModel : ObservableObject
         PeriodScheduleService periodSchedule, AttendanceBalanceService attendanceBalance, SchoolYearService sy,
         DashboardSettingsService dashboardSettings, ISchoolHolidayRepository schoolHolidays,
         PublicHolidayService publicHolidays, SchoolCalendarSettingsService calendarSettings,
-        ISubstitutionEntryRepository substitutions, IAnnualPlanEventRepository? annualPlanEvents = null,
+        ISubstitutionEntryRepository substitutions, ITimeEntryRepository timeEntries,
+        IAnnualPlanEventRepository? annualPlanEvents = null,
         AnnualPlanSyncService? annualPlanSync = null, SchoolWeatherService? schoolWeather = null)
     {
         _groups = groups; _subjects = subjects; _lessons = lessons; _exams = exams; _tasks = tasks;
@@ -127,6 +163,7 @@ public partial class DashboardViewModel : ObservableObject
         _timetableSlots = timetableSlots; _periodSchedule = periodSchedule;
         _attendanceBalance = attendanceBalance; _sy = sy; _dashboardSettings = dashboardSettings;
         _schoolHolidays = schoolHolidays; _publicHolidays = publicHolidays; _calendarSettings = calendarSettings;
+        _timeEntries = timeEntries;
         _substitutions = substitutions;
         _annualPlanEvents = annualPlanEvents;
         _schoolWeather = schoolWeather;
@@ -187,7 +224,7 @@ public partial class DashboardViewModel : ObservableObject
                 IsHighPriority = t.Priority == TaskPriority.High });
 
         CurrentGroups.Clear();
-        foreach (var g in groups.Values.OrderBy(g => g.Name))
+        foreach (var g in groups.Values)
             CurrentGroups.Add(new()
             {
                 GroupId = g.Id,
@@ -199,11 +236,40 @@ public partial class DashboardViewModel : ObservableObject
         LoadCalendar();
         LoadOpenExcuses(groups.Values.ToList(), today);
         LoadAttendanceWarnings(today);
+        LoadExamWeekLoads(groups, today);
+        LoadMissingTeachingTime(today);
         LoadSupportPlanReviews(today);
         LoadUpcomingDates(groups, today);
         LoadOpenCorrections(groups, today);
         LoadUnplannedLessons(groups, today);
         LoadAlerts(groups, today);
+        UpdateDashboardSummary();
+    }
+
+    private void UpdateDashboardSummary()
+    {
+        TodayCard.IsEmpty = TodaysLessons.Count == 0;
+        TasksCard.IsEmpty = OpenTasks.Count == 0;
+        CalendarCard.IsEmpty = false;
+        ExcusesCard.IsEmpty = OpenExcuses.Count == 0;
+        UpcomingCard.IsEmpty = UpcomingDates.Count == 0;
+        CorrectionsCard.IsEmpty = OpenCorrections.Count == 0;
+        UnplannedCard.IsEmpty = UnplannedLessons.Count == 0;
+        AlertsCard.IsEmpty = Alerts.Count == 0;
+        AttendanceCard.IsEmpty = AttendanceWarnings.Count == 0;
+        ExamLoadCard.IsEmpty = ExamWeekLoads.Count == 0;
+        MissingTeachingTimeCard.IsEmpty = MissingTeachingTimeEntries.Count == 0;
+        SupportCard.IsEmpty = SupportPlanReviews.Count == 0;
+        GroupsCard.IsEmpty = CurrentGroups.Count == 0;
+
+        OnPropertyChanged(nameof(TodayLessonCount));
+        OnPropertyChanged(nameof(OpenTaskCount));
+        OnPropertyChanged(nameof(UpcomingCount));
+        OnPropertyChanged(nameof(AttentionCount));
+        OnPropertyChanged(nameof(TodayLessonSummary));
+        OnPropertyChanged(nameof(OpenTaskSummary));
+        OnPropertyChanged(nameof(AttentionSummary));
+        OnPropertyChanged(nameof(UpcomingSummary));
     }
 
     private async Task LoadWeatherAsync()
@@ -266,12 +332,16 @@ public partial class DashboardViewModel : ObservableObject
         var from = _sy.SchoolYearStart(schoolYear);
         var to = _sy.SchoolYearEnd(schoolYear);
 
+        // Ein Bulk-Laden aller Sitzungen vermeidet, für jeden Mitarbeits-Eintrag jedes Schülers
+        // einzeln GetById aufzurufen (N+1 bei vielen Schülern/Einträgen).
+        var sessionDates = _participationSessions.GetAll().ToDictionary(s => s.Id, s => s.Date);
+
         var items = new List<AttendanceWarningItem>();
         foreach (var student in _students.GetAll())
         {
             var entries = _participationEntries.GetByStudent(student.Id)
-                .Select(e => _participationSessions.GetById(e.SessionId) is { } session
+                .Select(e => sessionDates.TryGetValue(e.SessionId, out var date)
-                    ? ((DateOnly?)session.Date, e.Attendance) : (null, e.Attendance))
+                    ? ((DateOnly?)date, e.Attendance) : (null, e.Attendance))
                 .Where(t => t.Item1.HasValue)
                 .Select(t => (t.Item1!.Value, t.Attendance));
 
@@ -283,6 +353,75 @@ public partial class DashboardViewModel : ObservableObject
             AttendanceWarnings.Add(item);
     }
 
+    // ── Klausurwochen (Nutzer-Feedback) ───────────────────────────────────────
+    //
+    // Persönliche Klausurlast über alle Kurse hinweg — anders als die klassenbezogene
+    // Kollisionsprüfung, die bereits der schulische Klausurplaner übernimmt (siehe
+    // ExamWeekLoadService). Nur geplante, noch bevorstehende Klausuren zählen: die
+    // Vorausschau soll helfen, eine sich anbahnende Woche zu erkennen, bevor man eine weitere
+    // Klausur genau dort einträgt — bereits durchgeführte/korrigierte Klausuren werden schon
+    // von der Karte "Offene Korrekturen" abgedeckt.
+
+    private void LoadExamWeekLoads(IReadOnlyDictionary<Guid, LearningGroup> groups, DateOnly today)
+    {
+        ExamWeekLoads.Clear();
+        var lastDay = today.AddDays(ExamLoadLookaheadDays);
+        var upcoming = groups.Keys
+            .SelectMany(gid => _exams.GetByGroup(gid))
+            .Where(e => e.Status == ExamStatus.Planned && e.Date >= today && e.Date <= lastDay);
+
+        foreach (var week in ExamWeekLoadService.FindOverloadedWeeks(upcoming))
+            ExamWeekLoads.Add(new ExamWeekLoadItem(week.IsoWeek, week.WeekStart, week.WeekEnd, week.ExamCount));
+    }
+
+    // ── Unterrichtszeit-Erfassung nachholen (Nutzer-Feedback) ─────────────────
+    //
+    // "Ich vergesse es, und fasse die App außerhalb der Schule manchmal nicht mehr an" — schaut
+    // deshalb bewusst ein paar Tage zurück statt nur auf heute. Ein Tag zählt als erfasst, sobald
+    // irgendein TimeEntry der Kategorie "Unterricht" an diesem Datum existiert; die genaue
+    // Zeitüberschneidung mit dem Stundenplan wird nicht geprüft (dieselbe grobe Betrachtung wie
+    // beim bestehenden "Unterrichtszeit übernehmen"-Vorschlag für heute).
+
+    private void LoadMissingTeachingTime(DateOnly today)
+    {
+        MissingTeachingTimeEntries.Clear();
+        var firstDay = today.AddDays(-MissingTeachingTimeLookbackDays);
+        var publicHolidayDates = Enumerable.Range(firstDay.Year, today.Year - firstDay.Year + 1)
+            .SelectMany(y => _publicHolidays.GetHolidays(y, _calendarSettings.State))
+            .Select(h => h.Date).ToHashSet();
+        var schoolHolidays = _schoolHolidays.GetAll();
+        var nowTime = TimeOnly.FromDateTime(DateTime.Now);
+
+        var items = new List<MissingTeachingTimeItem>();
+        for (var date = firstDay; date <= today; date = date.AddDays(1))
+        {
+            if (IsFreeDay(date, schoolHolidays, publicHolidayDates)) continue;
+
+            var daySlots = _timetableSlots.GetAll().Where(s => s.Weekday == date.DayOfWeek).ToList();
+            if (daySlots.Count == 0) continue;
+
+            var cancelledPeriods = _substitutions.GetByDate(date)
+                .Where(s => s.Kind == SubstitutionKind.Cancelled)
+                .Select(s => s.PeriodNumber).ToHashSet();
+            var periodTimes = daySlots.Where(s => !cancelledPeriods.Contains(s.PeriodNumber))
+                .Select(s => _periodSchedule.GetTimes(s.PeriodNumber))
+                .Where(t => t is not null).Select(t => t!.Value).ToList();
+            if (periodTimes.Count == 0) continue; // alle Stunden entfallen oder kein Zeitraster hinterlegt
+
+            var lastPeriodEnd = periodTimes.Max(t => t.End);
+            if (date == today && nowTime < lastPeriodEnd.AddMinutes(MissingTeachingTimeTodayDelayMinutes))
+                continue; // heute: erst 30 Minuten nach Unterrichtsschluss erinnern
+
+            if (_timeEntries.GetByDate(date).Any(e => e.Category == "Unterricht")) continue;
+
+            var windowStart = periodTimes.Min(t => t.Start).AddMinutes(-TeachingWindowBufferBeforeMinutes);
+            var windowEnd = lastPeriodEnd.AddMinutes(TeachingWindowBufferAfterMinutes);
+            items.Add(new MissingTeachingTimeItem(date, windowStart, windowEnd));
+        }
+        foreach (var item in items.OrderBy(i => i.Date))
+            MissingTeachingTimeEntries.Add(item);
+    }
+
     // ── Förderplan-Wiedervorlage (5.3.2) ──────────────────────────────────────
 
     private void LoadSupportPlanReviews(DateOnly today)
@@ -352,12 +491,10 @@ public partial class DashboardViewModel : ObservableObject
                      .Where(e => e.Status is ExamStatus.Conducted or ExamStatus.Graded)
                      .OrderBy(e => e.Date))
         {
-            var expected = _memberships.GetByGroup(group.Id)
+            var (expected, evaluated) = ExamCorrectionCounter.Count(exam,
-                .Count(m => GroupMembershipService.IsActiveOn(m, exam.Date));
+                _memberships.GetByGroup(group.Id), _examResults.GetByExam(exam.Id));
-            var evaluated = _examResults.GetByExam(exam.Id)
-                .Count(r => r.Absent || !string.IsNullOrWhiteSpace(r.Grade) || r.Points.Count > 0);
             OpenCorrections.Add(new CorrectionProgressItem(exam.Id, group.Id, exam.Title,
-                group.Name, exam.Date, Math.Min(evaluated, expected), expected, today));
+                group.Name, exam.Date, evaluated, expected, today));
         }
     }
 
@@ -510,7 +647,8 @@ public partial class DashboardViewModel : ObservableObject
         "excuses" => "Offene Entschuldigungen", "upcoming" => "Anstehende Termine",
         "corrections" => "Offene Korrekturen", "unplanned" => "Ungeplante Stunden", "alerts" => "Auffälligkeiten",
         "attendance" => "Fehlzeiten-Warnung", "support" => "Förderplan-Wiedervorlage",
-        "groups" => "Meine Lerngruppen", _ => key,
+        "groups" => "Meine Lerngruppen", "examload" => "Klausurwochen",
+        "missingteachingtime" => "Unterrichtszeit nacherfassen", _ => key,
     };
 
     private void ApplyCardLayout()
@@ -560,6 +698,15 @@ public partial class DashboardViewModel : ObservableObject
     [RelayCommand] private void OpenStudentSupportPlan(SupportPlanDueItem? item)
     { if (item is not null) OnNavigateToStudent?.Invoke(item.StudentId); }
 
+    [RelayCommand]
+    private async Task AddMissingTeachingTime(MissingTeachingTimeItem? item)
+    {
+        if (item is null || OnAddMissingTeachingTime is null) return;
+        await OnAddMissingTeachingTime(item);
+        LoadMissingTeachingTime(DateOnly.FromDateTime(DateTime.Today));
+        UpdateDashboardSummary();
+    }
+
     private void LoadOpenExcuses(List<LearningGroup> groups, DateOnly today)
     {
         OpenExcuses.Clear();
@@ -592,6 +739,7 @@ public partial class DashboardViewModel : ObservableObject
         entry.Attendance = status;
         _participationEntries.Save(entry);
         OpenExcuses.Remove(item);
+        UpdateDashboardSummary();
     }
 
     private void LoadCalendar()
@@ -716,9 +864,35 @@ public partial class DashboardViewModel : ObservableObject
     {
         if (day is null) return;
         foreach (var cell in CalendarDays) cell.IsSelected = cell == day;
+        SelectedCalendarDate = day.Date;
         SelectedDayLabel = day.Date.ToString("dddd, d. MMMM", De);
         SelectedDayEvents.Clear();
         foreach (var item in day.Events) SelectedDayEvents.Add(item);
+        SortCurrentGroups(day.Date);
+    }
+
+    private void SortCurrentGroups(DateOnly date)
+    {
+        var schoolHolidays = _schoolHolidays.GetAll();
+        var publicHolidays = _publicHolidays.GetHolidays(date.Year, _calendarSettings.State)
+            .Select(h => h.Date).ToHashSet();
+        var isFreeDay = IsFreeDay(date, schoolHolidays, publicHolidays);
+        var cancelledPeriods = _substitutions.GetByDate(date)
+            .Where(s => s.Kind == SubstitutionKind.Cancelled)
+            .Select(s => s.PeriodNumber).ToHashSet();
+
+        foreach (var chip in CurrentGroups)
+        {
+            var hasLesson = _lessons.GetByGroupAndDate(chip.GroupId, date).Count > 0;
+            var hasActiveSlot = !isFreeDay && _timetableSlots.GetByGroup(chip.GroupId)
+                .Any(s => s.Weekday == date.DayOfWeek && !cancelledPeriods.Contains(s.PeriodNumber));
+            chip.IsOnSelectedDay = hasLesson || hasActiveSlot;
+        }
+
+        var sorted = CurrentGroups.OrderByDescending(g => g.IsOnSelectedDay)
+            .ThenBy(g => g.Name, StringComparer.CurrentCultureIgnoreCase).ToList();
+        CurrentGroups.Clear();
+        foreach (var chip in sorted) CurrentGroups.Add(chip);
     }
 
     [RelayCommand]
@@ -858,7 +1032,13 @@ public class LessonItem
     public bool HasRoom => !string.IsNullOrWhiteSpace(Room);
 }
 public class TaskItem   { public string Title { get; set; } = ""; public string DueDate { get; set; } = ""; public bool IsOverdue { get; set; } public bool IsReminder { get; set; } public bool IsHighPriority { get; set; } }
-public class GroupChip  { public Guid GroupId { get; set; } public string Name { get; set; } = ""; public string Subject { get; set; } = ""; }
+public class GroupChip
+{
+    public Guid GroupId { get; set; }
+    public string Name { get; set; } = "";
+    public string Subject { get; set; } = "";
+    public bool IsOnSelectedDay { get; set; }
+}
 
 // ── Offene Entschuldigungen (aus Mitarbeit-Fehltagen) ────────────────────────
 
@@ -896,6 +1076,23 @@ public class AttendanceWarningItem(Guid studentId, string studentName, double ab
     public double AbsenceRatePercent { get; } = absenceRatePercent;
 }
 
+public class ExamWeekLoadItem(int isoWeek, DateOnly weekStart, DateOnly weekEnd, int examCount)
+{
+    public int ExamCount { get; } = examCount;
+    public string Label => $"KW {isoWeek} ({weekStart:dd.MM.}–{weekEnd:dd.MM.})";
+    public string CountDisplay => ExamCount == 1 ? "1 Klausur" : $"{ExamCount} Klausuren";
+}
+
+public class MissingTeachingTimeItem(DateOnly date, TimeOnly windowStart, TimeOnly windowEnd)
+{
+    private static readonly CultureInfo De = new("de-DE");
+
+    public DateOnly Date { get; } = date;
+    public TimeOnly WindowStart { get; } = windowStart;
+    public TimeOnly WindowEnd { get; } = windowEnd;
+    public string DateDisplay { get; } = date.ToString("dddd, dd.MM.", De);
+}
+
 // ── Förderplan-Wiedervorlage (5.3.2) ──────────────────────────────────────────
 
 public class SupportPlanDueItem
@@ -1034,18 +1231,29 @@ public sealed class DashboardAlertItem(Guid studentId, Guid? groupId, string stu
 public partial class DashboardCardOption : ObservableObject
 {
     [ObservableProperty] private bool _isVisible;
+    [ObservableProperty] private bool _isEmpty;
     [ObservableProperty] private int _row;
     [ObservableProperty] private int _column;
     public string Key { get; }
     public string Title { get; }
+    public bool HideWhenEmpty { get; }
+    public bool EffectiveIsVisible => IsVisible && (!HideWhenEmpty || !IsEmpty);
     public Action? OnVisibilityChanged { get; set; }
 
     public DashboardCardOption(string key, string title, bool isVisible)
     {
         Key = key;
         Title = title;
+        HideWhenEmpty = key is "excuses" or "upcoming" or "corrections" or "unplanned"
+            or "alerts" or "attendance" or "support";
         _isVisible = isVisible;
     }
 
-    partial void OnIsVisibleChanged(bool value) => OnVisibilityChanged?.Invoke();
+    partial void OnIsVisibleChanged(bool value)
+    {
+        OnPropertyChanged(nameof(EffectiveIsVisible));
+        OnVisibilityChanged?.Invoke();
+    }
+
+    partial void OnIsEmptyChanged(bool value) => OnPropertyChanged(nameof(EffectiveIsVisible));
 }

LehrerApp.Desktop/ViewModels/Exams/ExamsOverviewViewModel.cs

@@ -0,0 +1,259 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Desktop.ViewModels.Groups;
+using System.Collections.ObjectModel;
+using System.Globalization;
+
+namespace LehrerApp.Desktop.ViewModels.Exams;
+
+/// Klausuren-Hauptseite (Sidebar "Klausuren"): gruppenübergreifende Liste aller Klausuren des
+/// aktuellen Schuljahres, sortiert nach einem unsichtbaren Prioritäts-Score
+/// (`ExamPriorityService`) statt nach Datum — unbearbeitete/überfällige Korrekturen oben,
+/// erledigte unten. Oben ein Detailbereich zur ausgewählten Klausur, der sich je nach Status
+/// unterscheidet (Korrekturfortschritt vs. Notenspiegel), inklusive Umschalter für Parallelkurse
+/// (gleiche Arbeit, mehrere Kurse — siehe `Exam.SharedExamGroupId`).
+public partial class ExamsOverviewViewModel : ObservableObject
+{
+    private readonly IExamRepository _exams;
+    private readonly IExamResultRepository _examResults;
+    private readonly IGroupRepository _groups;
+    private readonly IGroupMembershipRepository _memberships;
+    private readonly GradingService _grading;
+    private readonly SchoolYearService _schoolYear;
+
+    public ObservableCollection<ExamListRowViewModel> Rows { get; } = [];
+    public ObservableCollection<ExamListRowViewModel> Siblings { get; } = [];
+    public ObservableCollection<GradeBarItem> DetailGradeDistribution { get; } = [];
+
+    [ObservableProperty] private ExamListRowViewModel? _selectedRow;
+    [ObservableProperty] private bool _hasSelection;
+    [ObservableProperty] private string _emptyHint = "";
+
+    [ObservableProperty] private bool _showCorrectionProgress;
+    [ObservableProperty] private string _progressLabel = "";
+    [ObservableProperty] private double _progressBarWidth;
+    [ObservableProperty] private bool _showGradeSummary;
+    [ObservableProperty] private string _averageLabel = "";
+    [ObservableProperty] private string _approvalLabel = "";
+    [ObservableProperty] private string _announcementLabel = "";
+
+    public Func<Exam, Task>? OnGradeExam { get; set; }
+    public Func<Exam, Task>? OnEvaluateExam { get; set; }
+    public Action<Guid>? OnNavigateToGroup { get; set; }
+    public Action? OnNavigateToGroups { get; set; }
+    public bool HasNoExams => Rows.Count == 0;
+
+    public ExamsOverviewViewModel(IExamRepository exams, IExamResultRepository examResults,
+        IGroupRepository groups, IGroupMembershipRepository memberships, GradingService grading,
+        SchoolYearService schoolYear)
+    {
+        _exams = exams; _examResults = examResults; _groups = groups;
+        _memberships = memberships; _grading = grading; _schoolYear = schoolYear;
+    }
+
+    [RelayCommand]
+    public void Load()
+    {
+        var selectedId = SelectedRow?.Exam.Id;
+        Rows.Clear();
+
+        var groups = _groups.GetBySchoolYear(_schoolYear.CurrentSchoolYear());
+        var today = DateOnly.FromDateTime(DateTime.Today);
+
+        var rows = new List<ExamListRowViewModel>();
+        foreach (var group in groups)
+        {
+            var groupMemberships = _memberships.GetByGroup(group.Id);
+            foreach (var exam in _exams.GetByGroup(group.Id))
+            {
+                var (expected, evaluated) = ExamCorrectionCounter.Count(exam, groupMemberships,
+                    _examResults.GetByExam(exam.Id));
+                var info = ExamPriorityService.Evaluate(exam, expected, evaluated, today);
+                rows.Add(new ExamListRowViewModel(exam, group, expected, evaluated, info, today));
+            }
+        }
+
+        // Parallelkurse markieren, damit die Liste einen Verknüpfungs-Hinweis zeigen kann.
+        foreach (var group in rows.GroupBy(r => r.Exam.SharedExamGroupId ?? r.Exam.Id))
+        {
+            if (group.Count() <= 1) continue;
+            foreach (var row in group) row.HasSibling = true;
+        }
+
+        foreach (var row in rows.OrderByDescending(r => r.Score))
+            Rows.Add(row);
+
+        EmptyHint = Rows.Count == 0 ? "Keine Klausuren angelegt." : "";
+        OnPropertyChanged(nameof(HasNoExams));
+        SelectedRow = selectedId is { } id
+            ? Rows.FirstOrDefault(r => r.Exam.Id == id) ?? Rows.FirstOrDefault()
+            : Rows.FirstOrDefault();
+    }
+
+    partial void OnSelectedRowChanged(ExamListRowViewModel? value) => UpdateDetail(value);
+
+    private void UpdateDetail(ExamListRowViewModel? row)
+    {
+        HasSelection = row is not null;
+        Siblings.Clear();
+        DetailGradeDistribution.Clear();
+        ShowCorrectionProgress = false;
+        ShowGradeSummary = false;
+        if (row is null) return;
+
+        ApprovalLabel = row.Exam.ApprovalGrantedAt is { } a
+            ? $"Genehmigt am {a.ToString("dd.MM.yyyy", CultureInfo.InvariantCulture)}"
+            : "Genehmigung noch ausstehend";
+        AnnouncementLabel = row.Exam.AnnouncedAt is { } n
+            ? $"Angekündigt am {n.ToString("dd.MM.yyyy", CultureInfo.InvariantCulture)}"
+            : "Noch nicht angekündigt";
+
+        if (row.HasSibling)
+        {
+            var anchor = row.Exam.SharedExamGroupId ?? row.Exam.Id;
+            foreach (var sibling in Rows.Where(r => r != row && (r.Exam.SharedExamGroupId ?? r.Exam.Id) == anchor))
+                Siblings.Add(sibling);
+        }
+
+        ShowCorrectionProgress = row.Status is ExamListStatus.AwaitingCorrection
+            or ExamListStatus.CorrectionInProgress or ExamListStatus.CorrectionStuck;
+        if (ShowCorrectionProgress)
+        {
+            ProgressLabel = $"{row.Evaluated} / {row.Expected} korrigiert";
+            var fraction = row.Expected <= 0 ? 0 : Math.Clamp((double)row.Evaluated / row.Expected, 0, 1);
+            ProgressBarWidth = fraction * 240.0;
+        }
+
+        ShowGradeSummary = row.Status is ExamListStatus.AwaitingReturn or ExamListStatus.Returned;
+        if (ShowGradeSummary) LoadGradeSummary(row);
+    }
+
+    private void LoadGradeSummary(ExamListRowViewModel row)
+    {
+        var grades = _examResults.GetByExam(row.Exam.Id)
+            .Where(r => !r.Absent && !string.IsNullOrWhiteSpace(r.Grade))
+            .Select(r => r.Grade!).ToList();
+        if (grades.Count == 0) { AverageLabel = "Noch keine Noten erfasst."; return; }
+
+        AverageLabel = "Ø " + _grading.WeightedAverage(grades.Select(g => (Grade: g, Weight: 1.0)).ToList())
+            .ToString("0.00", CultureInfo.InvariantCulture);
+
+        var counts = grades.GroupBy(g => g).ToDictionary(g => g.Key, g => g.Count());
+        var maxCount = counts.Count == 0 ? 0 : counts.Values.Max();
+        foreach (var entry in row.Exam.GradingKey.OrderByDescending(e => e.MinPercent))
+        {
+            counts.TryGetValue(entry.Grade, out var count);
+            DetailGradeDistribution.Add(new GradeBarItem(entry.Grade, count, grades.Count, maxCount));
+        }
+    }
+
+    [RelayCommand]
+    private void SelectExam(ExamListRowViewModel row) => SelectedRow = row;
+
+    [RelayCommand]
+    private async Task GradeSelected()
+    {
+        if (SelectedRow is null || OnGradeExam is null) return;
+        await OnGradeExam(SelectedRow.Exam);
+        Load();
+    }
+
+    [RelayCommand]
+    private async Task EvaluateSelected()
+    {
+        if (SelectedRow is null || OnEvaluateExam is null) return;
+        await OnEvaluateExam(SelectedRow.Exam);
+        Load();
+    }
+
+    [RelayCommand]
+    private void GoToGroup()
+    {
+        if (SelectedRow is null) return;
+        OnNavigateToGroup?.Invoke(SelectedRow.GroupId);
+    }
+
+    [RelayCommand]
+    private void GoToGroups() => OnNavigateToGroups?.Invoke();
+
+    [RelayCommand]
+    private void ToggleApproval() => ToggleDate(SelectedRow?.Exam, e => e.ApprovalGrantedAt,
+        (e, v) => e.ApprovalGrantedAt = v);
+
+    [RelayCommand]
+    private void ToggleAnnouncement() => ToggleDate(SelectedRow?.Exam, e => e.AnnouncedAt,
+        (e, v) => e.AnnouncedAt = v);
+
+    private void ToggleDate(Exam? exam, Func<Exam, DateOnly?> get, Action<Exam, DateOnly?> set)
+    {
+        if (exam is null) return;
+        set(exam, get(exam) is null ? DateOnly.FromDateTime(DateTime.Today) : null);
+        exam.UpdatedAt = DateTime.UtcNow;
+        _exams.Save(exam);
+        UpdateDetail(SelectedRow);
+    }
+}
+
+// ── Zeile in der Klausurliste ────────────────────────────────────────────────
+
+public class ExamListRowViewModel
+{
+    public Exam Exam { get; }
+    public Guid GroupId { get; }
+    public string Title { get; }
+    public string GroupLabel { get; }
+    public int Expected { get; }
+    public int Evaluated { get; }
+    public ExamListStatus Status { get; }
+    public double Score { get; }
+    public string StatusLabel { get; }
+    public string SubLabel { get; }
+    public bool HasSibling { get; set; }
+
+    public bool IsOk { get; }
+    public bool IsInfo { get; }
+    public bool IsWarning { get; }
+    public bool IsDanger { get; }
+
+    public ExamListRowViewModel(Exam exam, LearningGroup group, int expected, int evaluated,
+        ExamPriorityInfo info, DateOnly today)
+    {
+        Exam = exam; GroupId = group.Id; Title = exam.Title; GroupLabel = group.Name;
+        Expected = expected; Evaluated = evaluated; Status = info.Status; Score = info.Score;
+
+        (StatusLabel, SubLabel, IsOk, IsInfo, IsWarning, IsDanger) = Status switch
+        {
+            ExamListStatus.Planned => ("Geplant", $"geplant für {RelativeDay(exam.Date, today)}",
+                false, false, false, false),
+            ExamListStatus.AwaitingCorrection when today.DayNumber - exam.Date.DayNumber <= 3 =>
+                ("Korrektur ausstehend", $"geschrieben {RelativeDay(exam.Date, today)}",
+                    false, false, true, false),
+            ExamListStatus.AwaitingCorrection =>
+                ("überfällig", $"geschrieben {RelativeDay(exam.Date, today)}", false, false, false, true),
+            ExamListStatus.CorrectionInProgress =>
+                ("Korrektur läuft", $"{evaluated}/{expected} korrigiert", false, false, true, false),
+            ExamListStatus.CorrectionStuck =>
+                ("hängt fest", $"{evaluated}/{expected} korrigiert", false, false, false, false),
+            ExamListStatus.AwaitingReturn => ("Korrigiert", "Rückgabe aussteht", false, true, false, false),
+            ExamListStatus.Returned => ("Abgeschlossen",
+                exam.ReturnedAt is { } r ? $"zurückgegeben {r:dd.MM.yyyy}" : "zurückgegeben", true, false, false, false),
+            _ => ("", "", false, false, false, false),
+        };
+    }
+
+    private static string RelativeDay(DateOnly date, DateOnly today)
+    {
+        var diff = date.DayNumber - today.DayNumber;
+        return diff switch
+        {
+            0 => "heute",
+            1 => "morgen",
+            -1 => "gestern",
+            > 1 => $"in {diff} Tagen",
+            _ => $"vor {-diff} Tagen",
+        };
+    }
+}

LehrerApp.Desktop/ViewModels/GlobalSearchViewModel.cs

@@ -0,0 +1,215 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using System.Collections.ObjectModel;
+
+namespace LehrerApp.Desktop.ViewModels;
+
+/// <summary>
+/// Globale Suche und Schnellerfassung (14.2). Die Projektion bleibt bewusst klein und lokal:
+/// durchsucht werden die wichtigsten täglichen Ziele, ohne dafür einen zusätzlichen Suchindex
+/// oder eine Netzwerkabhängigkeit einzuführen.
+/// </summary>
+public partial class GlobalSearchViewModel : ObservableObject
+{
+    private const int MaxDataResults = 12;
+
+    private readonly IStudentRepository _students;
+    private readonly IGroupRepository _groups;
+    private readonly ISubjectRepository _subjects;
+    private readonly IExamRepository _exams;
+    private readonly IWorkTaskRepository _tasks;
+
+    [ObservableProperty] private string _query = "";
+    [ObservableProperty] private GlobalSearchResult? _selectedResult;
+
+    public ObservableCollection<GlobalSearchResult> Results { get; } = [];
+    public bool HasResults => Results.Count > 0;
+    public bool ShowNoResults => !string.IsNullOrWhiteSpace(Query) && Results.Count == 0;
+
+    public Action<GlobalSearchResult>? OnNavigate { get; set; }
+    public Func<bool, Task>? OnQuickAddTask { get; set; }
+    public Func<Task>? OnQuickAddStudent { get; set; }
+    public Func<Task>? OnQuickAddGroupDocumentation { get; set; }
+    public Action? OnClose { get; set; }
+
+    public GlobalSearchViewModel(IStudentRepository students, IGroupRepository groups,
+        ISubjectRepository subjects, IExamRepository exams, IWorkTaskRepository tasks)
+    {
+        _students = students;
+        _groups = groups;
+        _subjects = subjects;
+        _exams = exams;
+        _tasks = tasks;
+        RefreshResults();
+    }
+
+    partial void OnQueryChanged(string value) => RefreshResults();
+
+    public void Reset()
+    {
+        Query = "";
+        RefreshResults();
+    }
+
+    private void RefreshResults()
+    {
+        Results.Clear();
+        var query = Query.Trim();
+
+        AddQuickActions(query);
+
+        if (query.Length > 0)
+        {
+            var groups = _groups.GetAll().Where(g => g.IsActive).ToList();
+            var groupNames = groups.ToDictionary(g => g.Id, g => g.Name);
+            var subjects = _subjects.GetAll().ToDictionary(s => s.Id);
+            Subject? GroupSubject(LearningGroup group) => group.SubjectId is { } subjectId
+                ? subjects.GetValueOrDefault(subjectId)
+                : null;
+            static string SubjectLabel(Subject? subject) => subject is null ? ""
+                : string.IsNullOrWhiteSpace(subject.ShortName)
+                    || subject.Name.Equals(subject.ShortName, StringComparison.CurrentCultureIgnoreCase)
+                    ? subject.Name
+                    : $"{subject.ShortName} – {subject.Name}";
+            var candidates = new List<GlobalSearchResult>();
+
+            candidates.AddRange(_students.GetAll().Where(s => s.IsActive)
+                .Where(s => Matches(s.FullName, query))
+                .Select(s => GlobalSearchResult.ForStudent(s)));
+
+            candidates.AddRange(groups
+                .Where(g => Matches($"{g.Name} {GroupSubject(g)?.Name} {GroupSubject(g)?.ShortName} {g.SchoolYear} {g.GradeLevel}", query))
+                .Select(g => GlobalSearchResult.ForGroup(g, SubjectLabel(GroupSubject(g)))));
+
+            candidates.AddRange(_exams.GetAll()
+                .Where(e => groupNames.ContainsKey(e.GroupId))
+                .Where(e => Matches($"{e.Title} {groupNames.GetValueOrDefault(e.GroupId)}", query))
+                .Select(e => GlobalSearchResult.ForExam(e, groupNames.GetValueOrDefault(e.GroupId) ?? "")));
+
+            candidates.AddRange(_tasks.GetAll()
+                .Where(t => t.GroupId is null || groupNames.ContainsKey(t.GroupId.Value))
+                .Where(t => Matches($"{t.Title} {t.Notes} {groupNames.GetValueOrDefault(t.GroupId ?? Guid.Empty)}", query))
+                .Select(t => GlobalSearchResult.ForTask(t, groupNames.GetValueOrDefault(t.GroupId ?? Guid.Empty) ?? "")));
+
+            foreach (var item in candidates
+                         .OrderByDescending(x => x.Title.StartsWith(query, StringComparison.CurrentCultureIgnoreCase))
+                         .ThenBy(x => x.KindSortOrder)
+                         .ThenBy(x => x.Title)
+                         .Take(MaxDataResults))
+                Results.Add(item);
+        }
+
+        SelectedResult = Results.FirstOrDefault();
+        OnPropertyChanged(nameof(HasResults));
+        OnPropertyChanged(nameof(ShowNoResults));
+    }
+
+    private void AddQuickActions(string query)
+    {
+        var actions = new[]
+        {
+            GlobalSearchResult.ForAction(GlobalSearchAction.NewTask, "Aufgabe anlegen", "Mit Fälligkeit, Gruppe und Priorität", "＋"),
+            GlobalSearchResult.ForAction(GlobalSearchAction.NewReminder, "Erinnerung anlegen", "Kurze Notiz ohne Zeiterfassung", "◷"),
+            GlobalSearchResult.ForAction(GlobalSearchAction.NewStudent, "Schüler anlegen", "Neue Stammdaten erfassen", "＋"),
+            GlobalSearchResult.ForAction(GlobalSearchAction.NewGroupDocumentation, "Lerngruppen-Eintrag", "Planung, Klausur oder Erinnerung dokumentieren", "N"),
+        };
+
+        foreach (var action in actions.Where(a => query.Length == 0 || Matches(a.Title, query)))
+            Results.Add(action);
+    }
+
+    private static bool Matches(string? value, string query) =>
+        value?.Contains(query, StringComparison.CurrentCultureIgnoreCase) == true;
+
+    [RelayCommand]
+    private async Task Execute(GlobalSearchResult? result)
+    {
+        if (result is null) return;
+
+        switch (result.Action)
+        {
+            case GlobalSearchAction.NewTask:
+                if (OnQuickAddTask is not null) await OnQuickAddTask(false);
+                break;
+            case GlobalSearchAction.NewReminder:
+                if (OnQuickAddTask is not null) await OnQuickAddTask(true);
+                break;
+            case GlobalSearchAction.NewStudent:
+                if (OnQuickAddStudent is not null) await OnQuickAddStudent();
+                break;
+            case GlobalSearchAction.NewGroupDocumentation:
+                if (OnQuickAddGroupDocumentation is not null) await OnQuickAddGroupDocumentation();
+                break;
+            default:
+                OnNavigate?.Invoke(result);
+                break;
+        }
+
+        OnClose?.Invoke();
+    }
+}
+
+public enum GlobalSearchResultKind { Action, Student, Group, Exam, Task }
+public enum GlobalSearchAction { None, NewTask, NewReminder, NewStudent, NewGroupDocumentation }
+
+public sealed class GlobalSearchResult
+{
+    public GlobalSearchResultKind Kind { get; private init; }
+    public GlobalSearchAction Action { get; private init; }
+    public Guid? EntityId { get; private init; }
+    public Guid? GroupId { get; private init; }
+    public string Title { get; private init; } = "";
+    public string Subtitle { get; private init; } = "";
+    public string Icon { get; private init; } = "";
+    public int KindSortOrder => Kind switch
+    {
+        GlobalSearchResultKind.Student => 0,
+        GlobalSearchResultKind.Group => 1,
+        GlobalSearchResultKind.Exam => 2,
+        GlobalSearchResultKind.Task => 3,
+        _ => -1,
+    };
+    public string KindLabel => Kind switch
+    {
+        GlobalSearchResultKind.Student => "Schüler",
+        GlobalSearchResultKind.Group => "Lerngruppe",
+        GlobalSearchResultKind.Exam => "Klausur",
+        GlobalSearchResultKind.Task => "Aufgabe",
+        _ => "Schnellaktion",
+    };
+
+    public static GlobalSearchResult ForAction(GlobalSearchAction action, string title, string subtitle, string icon) =>
+        new() { Kind = GlobalSearchResultKind.Action, Action = action, Title = title, Subtitle = subtitle, Icon = icon };
+
+    public static GlobalSearchResult ForStudent(Student student) => new()
+    {
+        Kind = GlobalSearchResultKind.Student, EntityId = student.Id,
+        Title = student.FullName, Subtitle = student.IsActive ? "Aktiv" : "Inaktiv", Icon = "P",
+    };
+
+    public static GlobalSearchResult ForGroup(LearningGroup group, string subjectName) => new()
+    {
+        Kind = GlobalSearchResultKind.Group, EntityId = group.Id, GroupId = group.Id,
+        Title = group.Name,
+        Subtitle = string.Join(" · ", new[] { subjectName, group.SchoolYear, $"Stufe {group.GradeLevel}" }
+            .Where(x => !string.IsNullOrWhiteSpace(x))),
+        Icon = "G",
+    };
+
+    public static GlobalSearchResult ForExam(Exam exam, string groupName) => new()
+    {
+        Kind = GlobalSearchResultKind.Exam, EntityId = exam.Id, GroupId = exam.GroupId,
+        Title = exam.Title, Subtitle = $"{groupName} · {exam.Date:dd.MM.yyyy}", Icon = "K",
+    };
+
+    public static GlobalSearchResult ForTask(WorkTask task, string groupName) => new()
+    {
+        Kind = GlobalSearchResultKind.Task, EntityId = task.Id, GroupId = task.GroupId,
+        Title = task.Title,
+        Subtitle = string.Join(" · ", new[] { groupName, task.DueDate?.ToString("dd.MM.yyyy") ?? "" }
+            .Where(x => !string.IsNullOrWhiteSpace(x))),
+        Icon = task.Kind == TaskKind.Reminder ? "E" : "A",
+    };
+}

LehrerApp.Desktop/ViewModels/Groups/ExamGradingViewModels.cs

@@ -1,4 +1,5 @@
 using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
 using LehrerApp.Core.Interfaces;
 using LehrerApp.Core.Models;
 using LehrerApp.Core.Services;
@@ -52,6 +53,16 @@ public partial class ExamGradingDialogViewModel : ObservableObject
 
     private void SaveRow(ExamResultRow row) => _results.Save(row.ToModel(_exam.Id));
 
+    /// Rest als abwesend markieren (Nutzerwunsch): Schüler, die nie nachschreiben, blockieren
+    /// sonst dauerhaft den live abgeleiteten Korrekturstatus (ExamPriorityService), weil niemand
+    /// eine leere Zeile anfasst, für die es nichts einzutragen gibt. Rührt bewusst nur unberührte
+    /// Zeilen an — bereits eingetragene Punkte/Kommentare bleiben unangetastet.
+    [RelayCommand]
+    private void MarkRemainingAbsent()
+    {
+        foreach (var row in Rows.Where(r => !r.Absent && r.Cells.All(c => c.Value is null)))
+            row.Absent = true;
+    }
 }
 
 // ── Zeile im Punkteraster ──────────────────────────────────────────────────

LehrerApp.Desktop/ViewModels/Groups/ExamViewModels.cs

@@ -21,6 +21,7 @@ public partial class ExamDialogViewModel : ObservableObject
     private readonly int _gradeLevel;
     private readonly GradingSystem _gradingSystem;
     private readonly Exam? _editingExam;
+    private readonly Exam? _duplicateSource;
     private readonly string _subjectName;
 
     [ObservableProperty] private string _title = "";
@@ -31,6 +32,7 @@ public partial class ExamDialogViewModel : ObservableObject
     [ObservableProperty] private string _titleError = "";
     [ObservableProperty] private string _dateTextError = "";
     [ObservableProperty] private string _returnedAtTextError = "";
+    [ObservableProperty] private string _weekLoadHint = "";
     [ObservableProperty] private double _totalPoints;
     [ObservableProperty] private bool _hasCompetencyCatalog;
     [ObservableProperty] private bool _useWeighting;
@@ -68,6 +70,7 @@ public partial class ExamDialogViewModel : ObservableObject
         _groupId = groupId; _subjectId = subjectId; _gradeLevel = gradeLevel;
         _gradingSystem = gradingSystem;
         _editingExam = editingExam;
+        _duplicateSource = duplicateSource;
         _subjectName = defaultSubjectName;
         IsDifferentiated = isDifferentiated;
 
@@ -106,6 +109,7 @@ public partial class ExamDialogViewModel : ObservableObject
         }
         foreach (var t in Tasks) t.ShowWeight = UseWeighting;
         RecomputeTotals();
+        UpdateWeekLoadHint();
     }
 
     partial void OnUseWeightingChanged(bool value)
@@ -113,6 +117,26 @@ public partial class ExamDialogViewModel : ObservableObject
         foreach (var t in Tasks) t.ShowWeight = value;
     }
 
+    partial void OnDateTextChanged(string value) => UpdateWeekLoadHint();
+
+    /// Nutzer-Feedback: persönliche Klausurlast pro Woche — die klassenbezogene
+    /// Kollisionsprüfung übernimmt bereits der schulische Klausurplaner (siehe
+    /// ExamWeekLoadService), hier geht es um die eigene Häufung über alle Kurse hinweg.
+    private void UpdateWeekLoadHint()
+    {
+        if (!DateOnly.TryParseExact(DateText, "dd.MM.yyyy", null, DateTimeStyles.None, out var date))
+        {
+            WeekLoadHint = "";
+            return;
+        }
+
+        var existing = ExamWeekLoadService.CountInSameWeek(_exams.GetAll(), date, _editingExam?.Id);
+        var totalIfSaved = existing + 1;
+        WeekLoadHint = totalIfSaved >= ExamWeekLoadService.WarningThreshold
+            ? $"Damit hättest du {totalIfSaved} Klausuren in dieser Woche."
+            : "";
+    }
+
     [RelayCommand]
     private void AddTask()
     {
@@ -304,6 +328,11 @@ public partial class ExamDialogViewModel : ObservableObject
         Result.Niveau     = NiveauDisplay.FromName(SelectedNiveauName);
         Result.Tasks      = Tasks.Select(t => t.ToModel()).ToList();
         Result.GradingKey = gradingKey;
+        // Parallelkurse (gleiche Arbeit, mehrere Kurse): beim Duplizieren verknüpfen, damit die
+        // Klausuren-Hauptseite zwischen ihnen umschalten kann. Der Anker ist die Id der zuerst
+        // angelegten Klausur der Kette — schon verknüpfte Quellen geben ihren Anker weiter.
+        if (_duplicateSource is not null)
+            Result.SharedExamGroupId = _duplicateSource.SharedExamGroupId ?? _duplicateSource.Id;
         _exams.Save(Result);
     }
 }

LehrerApp.Desktop/ViewModels/Groups/GradeOverviewViewModels.cs

@@ -54,6 +54,7 @@ public partial class GradeOverviewTabViewModel : ObservableObject
     public Func<GradeOverviewRow, Task>? OnManageStudentGrades { get; set; }
     public Func<Task>? OnCollectiveGrade { get; set; }
     public Func<Task>? OnReportGrades { get; set; }
+    public Func<GradeOverviewRow, Task>? OnShowPerformanceOverview { get; set; }
 
     public GradeOverviewTabViewModel(IGradeRepository grades, IExamRepository exams,
         IExamResultRepository results, IStudentRepository students,
@@ -107,6 +108,14 @@ public partial class GradeOverviewTabViewModel : ObservableObject
         Recompute();
     }
 
+    [RelayCommand]
+    private async Task ShowPerformanceOverview()
+    {
+        if (SelectedRow is null || OnShowPerformanceOverview is null) return;
+        await OnShowPerformanceOverview(SelectedRow);
+        Recompute();
+    }
+
     [RelayCommand]
     private async Task CollectiveGrade()
     {

LehrerApp.Desktop/ViewModels/Groups/GroupDocumentationViewModels.cs

@@ -25,6 +25,7 @@ public partial class GroupDocumentationTabViewModel : ObservableObject
     private List<StudentOption> _groupStudents = [];
 
     public static readonly StudentOption AllStudentsOption = new(Guid.Empty, "Alle Schüler");
+    public static readonly StudentOption WholeGroupOption = new(Guid.Empty, "Gesamte Lerngruppe");
 
     public ObservableCollection<DocumentationItem> Entries { get; } = [];
     public ObservableCollection<StudentOption> StudentFilterOptions { get; } = [AllStudentsOption];
@@ -62,8 +63,6 @@ public partial class GroupDocumentationTabViewModel : ObservableObject
     private void Load()
     {
         Entries.Clear();
-        if (_groupStudents.Count == 0) return;
-
         var studentNameById = _groupStudents.ToDictionary(s => s.Id, s => s.Name);
         var groupNameCache = new Dictionary<Guid, string>();
         string GroupLabel(Guid id)
@@ -80,6 +79,10 @@ public partial class GroupDocumentationTabViewModel : ObservableObject
 
         var all = relevantStudentIds
             .SelectMany(id => _docs.GetByStudent(id))
+            .Concat(SelectedStudentFilter.Id == Guid.Empty
+                ? _docs.GetAll().Where(d => d.StudentId == Guid.Empty && d.GroupId == _groupId)
+                : [])
+            .DistinctBy(d => d.Id)
             .Where(d => !OnlyThisGroup || d.GroupId == _groupId)
             .OrderByDescending(d => d.IsDraft)
             .ThenByDescending(d => d.Date)
@@ -90,7 +93,10 @@ public partial class GroupDocumentationTabViewModel : ObservableObject
         {
             var isOwnGroup = d.GroupId is null || d.GroupId == _groupId;
             var otherGroupLabel = isOwnGroup ? "" : GroupLabel(d.GroupId!.Value);
-            Entries.Add(new DocumentationItem(d, studentNameById.GetValueOrDefault(d.StudentId, ""),
+            var studentName = d.StudentId == Guid.Empty
+                ? WholeGroupOption.Name
+                : studentNameById.GetValueOrDefault(d.StudentId, "");
+            Entries.Add(new DocumentationItem(d, studentName,
                 isOwnGroup, otherGroupLabel));
         }
     }
@@ -100,7 +106,7 @@ public partial class GroupDocumentationTabViewModel : ObservableObject
     [RelayCommand]
     private async Task AddDocumentation()
     {
-        if (OnEditDocumentation is null || _groupStudents.Count == 0) return;
+        if (OnEditDocumentation is null) return;
         var result = await OnEditDocumentation(_groupId, _groupStudents, null);
         if (result is null) return;
         _docs.Save(result);

LehrerApp.Desktop/ViewModels/Groups/GroupOverviewViewModel.cs

@@ -33,12 +33,15 @@ public partial class GroupOverviewViewModel : ObservableObject
 
     private readonly ILessonRepository _lessons;
     private readonly IExamRepository _exams;
+    private readonly IExamResultRepository _examResults;
     private readonly IParticipationSessionRepository _sessions;
     private readonly IParticipationRepository _entries;
     private readonly IStudentRepository _students;
     private readonly IDocumentationRepository _documentation;
     private readonly IWorkTaskRepository _tasks;
+    private readonly IGroupRepository _groups;
     private readonly AttendanceBalanceService _attendanceBalance;
+    private readonly GradingService _grading;
     private readonly SchoolYearService _schoolYear;
 
     private Guid _groupId;
@@ -48,6 +51,8 @@ public partial class GroupOverviewViewModel : ObservableObject
     [ObservableProperty] private string _nextLessonLabel = "";
     [ObservableProperty] private bool _hasNextExam;
     [ObservableProperty] private string _nextExamLabel = "";
+    [ObservableProperty] private bool _hasYearComparison;
+    [ObservableProperty] private string _yearComparisonLabel = "";
     [ObservableProperty] private string _participationHintLabel = "";
     [ObservableProperty] private bool _participationHintIsStale;
     [ObservableProperty] private bool _hasOpenHomeworkCheck;
@@ -105,13 +110,14 @@ public partial class GroupOverviewViewModel : ObservableObject
     }
 
     public GroupOverviewViewModel(ILessonRepository lessons, IExamRepository exams,
-        IParticipationSessionRepository sessions, IParticipationRepository entries,
+        IExamResultRepository examResults, IParticipationSessionRepository sessions,
-        IStudentRepository students, IDocumentationRepository documentation, IWorkTaskRepository tasks,
+        IParticipationRepository entries, IStudentRepository students,
-        AttendanceBalanceService attendanceBalance, SchoolYearService schoolYear)
+        IDocumentationRepository documentation, IWorkTaskRepository tasks, IGroupRepository groups,
+        AttendanceBalanceService attendanceBalance, GradingService grading, SchoolYearService schoolYear)
     {
-        _lessons = lessons; _exams = exams; _sessions = sessions;
+        _lessons = lessons; _exams = exams; _examResults = examResults; _sessions = sessions;
         _entries = entries; _students = students; _documentation = documentation; _tasks = tasks;
-        _attendanceBalance = attendanceBalance; _schoolYear = schoolYear;
+        _groups = groups; _attendanceBalance = attendanceBalance; _grading = grading; _schoolYear = schoolYear;
     }
 
     public void Initialize(Guid groupId, string groupName)
@@ -126,6 +132,7 @@ public partial class GroupOverviewViewModel : ObservableObject
         var today = DateOnly.FromDateTime(DateTime.Today);
         LoadNextLesson(today);
         LoadNextExam(today);
+        LoadYearComparison();
         LoadParticipationHint(today);
         LoadOpenHomeworkCheck(today);
         LoadOpenExcuses(today);
@@ -138,7 +145,7 @@ public partial class GroupOverviewViewModel : ObservableObject
     private void LoadNextLesson(DateOnly today)
     {
         var next = _lessons.GetByGroupAndRange(_groupId, today, today.AddDays(NextLessonLookaheadDays))
-            .Where(l => l.Status == LessonStatus.Planned)
+            .Where(l => l.Status != LessonStatus.Conducted)
             .OrderBy(l => l.Date).ThenBy(l => l.LessonNumber ?? 0)
             .FirstOrDefault();
 
@@ -156,6 +163,38 @@ public partial class GroupOverviewViewModel : ObservableObject
         NextExamLabel = next is null ? "" : $"{next.Date:dd.MM.yyyy} — {next.Title}";
     }
 
+    // ── Klausurschnitt-Vorjahresvergleich (Nutzer-Feedback) ──────────────────
+    //
+    // Setzt voraus, dass diese Gruppe über GroupRolloverService aus einer Vorgängergruppe
+    // hochgestuft wurde (LearningGroup.PreviousGroupId) — vor Einführung dieses Felds
+    // hochgestufte Gruppen bleiben unverknüpft und zeigen keinen Vergleich. Nur sichtbar, wenn
+    // im Vorjahr tatsächlich Klausurergebnisse vorliegen; ohne die ist kein Vergleich möglich,
+    // auch wenn eine Verknüpfung besteht.
+
+    private void LoadYearComparison()
+    {
+        var group = _groups.GetById(_groupId);
+        var previous = group?.PreviousGroupId is Guid previousId ? ComputeExamAverage(previousId) : null;
+        if (previous is null) { HasYearComparison = false; return; }
+
+        var current = ComputeExamAverage(_groupId);
+        YearComparisonLabel = current is null
+            ? $"Vorjahr: Ø {previous.Value.Average:0.0} ({previous.Value.Count} Klausuren) — dieses Jahr noch keine Klausur."
+            : $"Dieses Jahr: Ø {current.Value.Average:0.0} ({current.Value.Count} Klausuren) · " +
+              $"Vorjahr: Ø {previous.Value.Average:0.0} ({previous.Value.Count} Klausuren)";
+        HasYearComparison = true;
+    }
+
+    private (double Average, int Count)? ComputeExamAverage(Guid groupId)
+    {
+        var grades = _exams.GetByGroup(groupId)
+            .SelectMany(e => _examResults.GetByExam(e.Id))
+            .Where(r => !r.Absent && !string.IsNullOrWhiteSpace(r.Grade))
+            .Select(r => (Grade: r.Grade!, Weight: 1.0))
+            .ToList();
+        return grades.Count == 0 ? null : (_grading.WeightedAverage(grades), grades.Count);
+    }
+
     /// Erinnert nicht an eine Note, sondern schlicht daran, überhaupt wieder eine Sitzung
     /// anzulegen — genau das vergisst man in Kursen, die man seltener unterrichtet, zuerst.
     private void LoadParticipationHint(DateOnly today)

LehrerApp.Desktop/ViewModels/Groups/GroupViewModels.cs

@@ -13,13 +13,8 @@ namespace LehrerApp.Desktop.ViewModels.Groups;
 
 public partial class GroupListViewModel : ObservableObject
 {
-    private const int QuickTasksMaxCount = 3;
-
     private readonly IGroupRepository _groups;
     private readonly ISubjectRepository _subjects;
-    private readonly ILessonRepository _lessons;
-    private readonly IExamRepository _exams;
-    private readonly IWorkTaskRepository _tasks;
 
     public Action<Guid, int>? OnNavigateToDetail { get; set; }
     public Func<Task>? OnAddGroup { get; set; }
@@ -29,11 +24,8 @@ public partial class GroupListViewModel : ObservableObject
 
     [ObservableProperty] private string _selectedSchoolYear = "";
     [ObservableProperty] private string _searchText = "";
-    [ObservableProperty] private GroupListItem? _selectedGroup;
     [ObservableProperty] private bool _showArchived;
 
-    public string SelectedGroupDisplayName => SelectedGroup?.DisplayName ?? "";
-    public string SelectedGroupSubtitle => SelectedGroup?.Subtitle ?? "";
     public string ListSummary => ShowArchived
         ? $"{Groups.Count} archivierte Gruppen · {SelectedSchoolYear}"
         : $"{Groups.Count} aktive Gruppen · {SelectedSchoolYear}";
@@ -45,22 +37,10 @@ public partial class GroupListViewModel : ObservableObject
     public ObservableCollection<string> SchoolYears { get; } = [];
     public ObservableCollection<GroupListItem> Groups { get; } = [];
 
-    // ── Schnellüberblick im Auswahl-Panel (Nutzer-Feedback: "oberhalb der Buttonliste ein paar
+    public GroupListViewModel(IGroupRepository groups, ISubjectRepository subjects, SchoolYearService sy)
-    // Daten auswerfen. Nächste Stunde, nächste Arbeit, wichtige Todos") — bewusst dieselben
-    // kompakten Kennzahlen wie die obersten Karten des Kurs-Dashboards (GroupOverviewViewModel),
-    // hier nur ohne eigenen Tab-Wechsel, da man ohnehin schon auf der Gruppenliste steht.
-    [ObservableProperty] private bool _quickHasNextLesson;
-    [ObservableProperty] private string _quickNextLessonLabel = "";
-    [ObservableProperty] private bool _quickHasNextExam;
-    [ObservableProperty] private string _quickNextExamLabel = "";
-    public ObservableCollection<GroupTaskItem> QuickTasks { get; } = [];
-    public bool QuickHasTasks => QuickTasks.Count > 0;
-    public bool QuickHasAnything => QuickHasNextLesson || QuickHasNextExam || QuickHasTasks;
-
-    public GroupListViewModel(IGroupRepository groups, ISubjectRepository subjects, SchoolYearService sy,
-        ILessonRepository lessons, IExamRepository exams, IWorkTaskRepository tasks)
     {
-        _groups = groups; _subjects = subjects; _lessons = lessons; _exams = exams; _tasks = tasks;
+        _groups = groups;
+        _subjects = subjects;
         foreach (var y in sy.RecentSchoolYears()) SchoolYears.Add(y);
         SelectedSchoolYear = sy.CurrentSchoolYear();
     }
@@ -68,58 +48,8 @@ public partial class GroupListViewModel : ObservableObject
     partial void OnSelectedSchoolYearChanged(string value) => LoadGroups();
     partial void OnSearchTextChanged(string value)          => LoadGroups();
     partial void OnShowArchivedChanged(bool value)           => LoadGroups();
-    partial void OnSelectedGroupChanged(GroupListItem? value)
-    {
-        OnPropertyChanged(nameof(SelectedGroupDisplayName));
-        OnPropertyChanged(nameof(SelectedGroupSubtitle));
-        NavigateToSectionCommand.NotifyCanExecuteChanged();
-        EditGroupCommand.NotifyCanExecuteChanged();
-        RollOverGroupCommand.NotifyCanExecuteChanged();
-        ToggleArchiveCommand.NotifyCanExecuteChanged();
-        DeleteGroupCommand.NotifyCanExecuteChanged();
-        LoadQuickInfo();
-    }
-
-    private void LoadQuickInfo()
-    {
-        QuickTasks.Clear();
-        if (SelectedGroup is null)
-        {
-            QuickHasNextLesson = false; QuickNextLessonLabel = "";
-            QuickHasNextExam = false; QuickNextExamLabel = "";
-            OnPropertyChanged(nameof(QuickHasTasks));
-            OnPropertyChanged(nameof(QuickHasAnything));
-            return;
-        }
-
-        var groupId = SelectedGroup.Id;
-        var today = DateOnly.FromDateTime(DateTime.Today);
-
-        var nextLesson = _lessons.GetByGroupAndRange(groupId, today, today.AddDays(90))
-            .Where(l => l.Status == LessonStatus.Planned)
-            .OrderBy(l => l.Date).ThenBy(l => l.LessonNumber ?? 0).FirstOrDefault();
-        QuickHasNextLesson = nextLesson is not null;
-        QuickNextLessonLabel = nextLesson is null ? ""
-            : string.IsNullOrWhiteSpace(nextLesson.Topic)
-                ? nextLesson.Date.ToString("dd.MM.yyyy")
-                : $"{nextLesson.Date:dd.MM.yyyy} — {nextLesson.Topic}";
-
-        var nextExam = _exams.GetByGroup(groupId).Where(e => e.Date >= today).MinBy(e => e.Date);
-        QuickHasNextExam = nextExam is not null;
-        QuickNextExamLabel = nextExam is null ? "" : $"{nextExam.Date:dd.MM.yyyy} — {nextExam.Title}";
-
-        foreach (var t in _tasks.GetByGroup(groupId).Where(t => t.Status != WorkTaskStatus.Done)
-                     .OrderBy(t => t.DueDate ?? DateOnly.MaxValue).Take(QuickTasksMaxCount))
-            QuickTasks.Add(new GroupTaskItem(t.Title, t.Kind == TaskKind.Reminder,
-                t.DueDate?.ToString("dd.MM.yyyy") ?? "", t.DueDate is { } d && d < today,
-                TaskPriorityDisplay.ColorHex(t.Priority), t.Priority == TaskPriority.High));
-        OnPropertyChanged(nameof(QuickHasTasks));
-        OnPropertyChanged(nameof(QuickHasAnything));
-    }
-
     public void LoadGroups()
     {
-        var selectedId = SelectedGroup?.Id;
         Groups.Clear();
         var all = _groups.GetBySchoolYear(SelectedSchoolYear, includeInactive: ShowArchived)
             .Where(g => g.IsActive != ShowArchived);
@@ -129,8 +59,18 @@ public partial class GroupListViewModel : ObservableObject
                           || (g.SubjectId is Guid id && subjectNames.GetValueOrDefault(id, "")
                               .Contains(SearchText, StringComparison.OrdinalIgnoreCase)));
         foreach (var g in filtered.OrderBy(g => g.Name))
-            Groups.Add(new GroupListItem(g, g.SubjectId is Guid id ? subjectNames.GetValueOrDefault(id, "") : ""));
+        {
-        SelectedGroup = Groups.FirstOrDefault(g => g.Id == selectedId);
+            var item = new GroupListItem(g,
+                g.SubjectId is Guid id ? subjectNames.GetValueOrDefault(id, "") : "")
+            {
+                OnOpen = OpenGroup,
+                OnEdit = EditGroup,
+                OnRollOver = RollOverGroup,
+                OnToggleArchive = ToggleArchive,
+                OnDelete = DeleteGroup,
+            };
+            Groups.Add(item);
+        }
         OnPropertyChanged(nameof(ListSummary));
         OnPropertyChanged(nameof(HasNoGroups));
         OnPropertyChanged(nameof(EmptyListMessage));
@@ -145,63 +85,57 @@ public partial class GroupListViewModel : ObservableObject
     }
     [RelayCommand] private void Refresh()   => LoadGroups();
 
-    [RelayCommand(CanExecute = nameof(CanEditSelectedGroup))]
+    [RelayCommand]
-    private async Task EditGroup()
+    private void OpenGroup(GroupListItem? group)
     {
-        if (SelectedGroup is null || OnEditGroup is null) return;
+        if (group is not null) OnNavigateToDetail?.Invoke(group.Id, 0);
-        var id = SelectedGroup.Id;
-        await OnEditGroup(id);
-        LoadGroups();
-        SelectedGroup = Groups.FirstOrDefault(g => g.Id == id);
     }
 
-    [RelayCommand(CanExecute = nameof(HasSelectedGroup))]
+    [RelayCommand]
-    private async Task RollOverGroup()
+    private async Task EditGroup(GroupListItem? group)
     {
-        if (SelectedGroup is null || OnRollOverGroup is null) return;
+        if (group?.IsActive != true || OnEditGroup is null) return;
-        var targetId = await OnRollOverGroup(SelectedGroup.Id);
+        var id = group.Id;
+        await OnEditGroup(id);
+        LoadGroups();
+    }
+
+    [RelayCommand]
+    private async Task RollOverGroup(GroupListItem? group)
+    {
+        if (group is null || OnRollOverGroup is null) return;
+        var targetId = await OnRollOverGroup(group.Id);
         if (targetId is null) return;
         var target = _groups.GetById(targetId.Value);
         if (target is null) return;
         if (!SchoolYears.Contains(target.SchoolYear)) SchoolYears.Insert(0, target.SchoolYear);
         SelectedSchoolYear = target.SchoolYear;
         LoadGroups();
-        SelectedGroup = Groups.FirstOrDefault(g => g.Id == target.Id);
+        OnNavigateToDetail?.Invoke(target.Id, 0);
     }
 
-    [RelayCommand(CanExecute = nameof(HasSelectedGroup))]
+    [RelayCommand]
-    private void ToggleArchive()
+    private void ToggleArchive(GroupListItem? selected)
     {
-        if (SelectedGroup is null) return;
+        if (selected is null) return;
-        var group = _groups.GetById(SelectedGroup.Id);
+        var group = _groups.GetById(selected.Id);
         if (group is null) return;
         group.IsActive = !group.IsActive;
         _groups.Save(group);
         LoadGroups();
     }
 
-    [RelayCommand(CanExecute = nameof(CanEditSelectedGroup))]
+    [RelayCommand]
-    private async Task DeleteGroup()
+    private async Task DeleteGroup(GroupListItem? group)
     {
-        if (SelectedGroup is null || OnConfirmDelete is null) return;
+        if (group?.IsActive != true || OnConfirmDelete is null) return;
-        var selected = SelectedGroup;
+        if (!await OnConfirmDelete(group)) return;
-        if (!await OnConfirmDelete(selected)) return;
+        _groups.Delete(group.Id);
-        _groups.Delete(selected.Id);
         LoadGroups();
     }
-
-    [RelayCommand(CanExecute = nameof(HasSelectedGroup))]
-    private void NavigateToSection(string? tabIndex)
-    {
-        if (SelectedGroup is null || !int.TryParse(tabIndex, out var tab)) return;
-        OnNavigateToDetail?.Invoke(SelectedGroup.Id, tab);
-    }
-
-    private bool HasSelectedGroup() => SelectedGroup is not null;
-    private bool CanEditSelectedGroup() => SelectedGroup?.IsActive == true;
 }
 
-public class GroupListItem
+public partial class GroupListItem : ObservableObject
 {
     public Guid Id { get; }
     public string Name { get; }
@@ -212,6 +146,13 @@ public class GroupListItem
     public string Subtitle { get; }
     public bool IsActive { get; }
     public string ArchiveActionLabel => IsActive ? "Archivieren" : "Wieder aktivieren";
+    public string OpenAutomationName => $"Lerngruppe {DisplayName} öffnen";
+    public string ManageAutomationName => $"Lerngruppe {DisplayName} verwalten";
+    public Action<GroupListItem>? OnOpen { get; init; }
+    public Func<GroupListItem, Task>? OnEdit { get; init; }
+    public Func<GroupListItem, Task>? OnRollOver { get; init; }
+    public Action<GroupListItem>? OnToggleArchive { get; init; }
+    public Func<GroupListItem, Task>? OnDelete { get; init; }
 
     public GroupListItem(LearningGroup g, string subjectName)
     {
@@ -224,6 +165,12 @@ public class GroupListItem
         DisplayName  = string.IsNullOrEmpty(subjectName) ? g.Name : $"{g.Name} · {subjectName}";
         Subtitle     = $"{TypeLabel} · Stufe {g.GradeLevel} · Noten {GradingLabel} · {g.SchoolYear}";
     }
+
+    [RelayCommand] private void Open() => OnOpen?.Invoke(this);
+    [RelayCommand] private Task Edit() => OnEdit?.Invoke(this) ?? Task.CompletedTask;
+    [RelayCommand] private Task RollOver() => OnRollOver?.Invoke(this) ?? Task.CompletedTask;
+    [RelayCommand] private void ToggleArchive() => OnToggleArchive?.Invoke(this);
+    [RelayCommand] private Task Delete() => OnDelete?.Invoke(this) ?? Task.CompletedTask;
 }
 
 // ── Gruppendetail ─────────────────────────────────────────────────────────────
@@ -878,6 +825,7 @@ public partial class AddGroupDialogViewModel : ObservableObject
     [ObservableProperty] private bool _isOwnClass;
     [ObservableProperty] private bool _isDifferentiated;
     [ObservableProperty] private bool _requiresLessonPlanning = true;
+    [ObservableProperty] private int? _webUntisLessonId;
     [ObservableProperty] private string _nameError = "";
     [ObservableProperty] private string _gradeLevelError = "";
 
@@ -917,6 +865,7 @@ public partial class AddGroupDialogViewModel : ObservableObject
         IsOwnClass = group.IsOwnClass;
         IsDifferentiated = group.IsDifferentiated;
         RequiresLessonPlanning = group.RequiresLessonPlanning;
+        WebUntisLessonId = group.WebUntisLessonId;
         OnPropertyChanged(nameof(DialogTitle));
         OnPropertyChanged(nameof(SaveButtonText));
     }
@@ -963,6 +912,7 @@ public partial class AddGroupDialogViewModel : ObservableObject
         Result.IsOwnClass    = IsOwnClass;
         Result.IsDifferentiated = IsDifferentiated;
         Result.RequiresLessonPlanning = RequiresLessonPlanning;
+        Result.WebUntisLessonId = WebUntisLessonId;
         _groups.Save(Result);
     }
 }

LehrerApp.Desktop/ViewModels/Groups/ParticipationViewModels.cs

@@ -158,6 +158,7 @@ public partial class ParticipationTabViewModel : ObservableObject
             row.OnCompetencyRatingChanged = (sid, code, val) => SaveCompetencyRating(sessionId, sid, code, val);
             row.HomeworkChangedCallback         = (sid, val) => SaveHomework(sessionId, sid, val);
             row.AttendanceChangedCallback       = (sid, val) => SaveAttendance(sessionId, sid, val);
+            row.DayHighlightChangedCallback     = (sid, val) => SaveDayHighlight(sessionId, sid, val);
             StudentRows.Add(row);
         }
         QuickInputCommand.NotifyCanExecuteChanged();
@@ -212,6 +213,15 @@ public partial class ParticipationTabViewModel : ObservableObject
         _entries.Save(entry);
     }
 
+    private void SaveDayHighlight(Guid sessionId, Guid studentId, DayHighlightKind? value)
+    {
+        if (IsReadOnly) return;
+        var entry = _entries.GetBySessionAndStudent(sessionId, studentId)
+                    ?? new ParticipationEntry { SessionId = sessionId, StudentId = studentId };
+        entry.DayHighlight = value;
+        _entries.Save(entry);
+    }
+
     [RelayCommand]
     private void ToggleCompetencyTags() => CompetencyTagsVisible = !CompetencyTagsVisible;
 
@@ -389,6 +399,7 @@ public partial class ParticipationStudentRow : ObservableObject
 
     [ObservableProperty] private HomeworkStatus? _homework;
     [ObservableProperty] private AttendanceStatus? _attendance;
+    [ObservableProperty] private DayHighlightKind? _dayHighlight;
 
     public string AttendanceLabel => AttendanceDisplay.ShortLabel(Attendance);
     public string AttendanceTooltip => AttendanceDisplay.Label(Attendance);
@@ -405,6 +416,7 @@ public partial class ParticipationStudentRow : ObservableObject
     public Action<Guid, string, int?>? OnCompetencyRatingChanged { get; set; }
     public Action<Guid, HomeworkStatus?>?  HomeworkChangedCallback   { get; set; }
     public Action<Guid, AttendanceStatus?>? AttendanceChangedCallback { get; set; }
+    public Action<Guid, DayHighlightKind?>? DayHighlightChangedCallback { get; set; }
 
     public ParticipationStudentRow(Guid id, string name, ParticipationEntry entry,
         List<AspectColumnDef> aspects, List<string> competencyCodes)
@@ -414,6 +426,7 @@ public partial class ParticipationStudentRow : ObservableObject
         _aspectDefs = aspects;
         _homework = HomeworkDisplay.Effective(entry);
         _attendance       = entry.Attendance;
+        _dayHighlight     = entry.DayHighlight;
 
         foreach (var a in aspects)
         {
@@ -463,6 +476,12 @@ public partial class ParticipationStudentRow : ObservableObject
         HomeworkChangedCallback?.Invoke(StudentId, value);
     }
 
+    public void SetDayHighlight(DayHighlightKind? value)
+    {
+        DayHighlight = value;
+        DayHighlightChangedCallback?.Invoke(StudentId, value);
+    }
+
     [RelayCommand]
     private void CycleAttendance()
     {
@@ -614,6 +633,27 @@ public static class AttendanceDisplay
     };
 }
 
+// ── Tagesflagge (Nutzer-Feedback) ──────────────────────────────────────────────
+
+public static class DayHighlightDisplay
+{
+    public static string Symbol(DayHighlightKind? kind) => kind switch
+    {
+        DayHighlightKind.Standout => "👑",
+        DayHighlightKind.Sleepy   => "😴",
+        DayHighlightKind.Rough    => "⚡",
+        _                         => "",
+    };
+
+    public static string Label(DayHighlightKind? kind) => kind switch
+    {
+        DayHighlightKind.Standout => "Spitzentag",
+        DayHighlightKind.Sleepy   => "Schlaftag",
+        DayHighlightKind.Rough    => "Schlechter Tag",
+        _                         => "Keine Markierung",
+    };
+}
+
 // ── Eine Bewertungszelle ──────────────────────────────────────────────────────
 
 public partial class RatingCell : ObservableObject
@@ -800,12 +840,31 @@ public partial class QuickInputViewModel : ObservableObject
     [ObservableProperty] private string _progressText = "";
     [ObservableProperty] private bool   _currentStudentIsAbsent;
     [ObservableProperty] private string _currentStudentAttendanceLabel = "";
+    [ObservableProperty] private DayHighlightKind? _currentStudentDayHighlight;
 
     /// Dimmt Name/Aspektliste, wenn der aktuelle Schüler abwesend ist — kein Blockieren der
     /// Eingabe (manche Bewertungssysteme wollen trotzdem einen Eintrag, z.B. "0 Punkte"), nur ein
     /// visueller Hinweis, dass eine Bewertung hier normalerweise keinen Sinn ergibt.
     public double CurrentStudentContentOpacity => CurrentStudentIsAbsent ? 0.4 : 1.0;
 
+    /// Tagesflagge (Nutzer-Feedback): Fallback für Kurse ohne Sitzplan — im Sitzplatz-Dialog gibt
+    /// es dieselbe Auswahl bereits über SeatAssessmentViewModel.DayHighlightChoices.
+    public string CurrentStudentDayHighlightSymbol => DayHighlightDisplay.Symbol(CurrentStudentDayHighlight);
+    public string CurrentStudentDayHighlightLabel => DayHighlightDisplay.Label(CurrentStudentDayHighlight);
+
+    public void SetDayHighlight(DayHighlightKind? value)
+    {
+        if (_rows.Count == 0) return;
+        _rows[StudentIndex].SetDayHighlight(value);
+        CurrentStudentDayHighlight = value;
+    }
+
+    partial void OnCurrentStudentDayHighlightChanged(DayHighlightKind? value)
+    {
+        OnPropertyChanged(nameof(CurrentStudentDayHighlightSymbol));
+        OnPropertyChanged(nameof(CurrentStudentDayHighlightLabel));
+    }
+
     public ObservableCollection<QuickAspectRow> AspectRows { get; } = [];
 
     /// Wechselt je nach Typ des aktuell gewählten Aspekts (3.1.3) — Scale3/Binary haben andere
@@ -824,7 +883,8 @@ public partial class QuickInputViewModel : ObservableObject
                 _ => "1–5 bewerten",
             };
             return $"{ratingHint}  ·  Q/W/E/R/T Aspekt wählen  ·  Leertaste/↓ nächster Aspekt  ·  ↑ vorheriger Aspekt  ·  " +
-                   "Enter/→ nächster Schüler  ·  Backspace/← vorheriger Schüler  ·  +/− anpassen  ·  Esc schließen";
+                   "Enter/→ nächster Schüler  ·  Backspace/← vorheriger Schüler  ·  +/− anpassen  ·  Entf nicht bewertet  ·  " +
+                   "⇧1/2/3 Tagesflagge, ⇧0 löschen  ·  Esc schließen";
         }
     }
 
@@ -852,6 +912,7 @@ public partial class QuickInputViewModel : ObservableObject
         ProgressText = $"{index + 1} / {_rows.Count}";
         CurrentStudentIsAbsent = row.IsAbsent;
         CurrentStudentAttendanceLabel = row.AttendanceTooltip;
+        CurrentStudentDayHighlight = row.DayHighlight;
 
         AspectRows.Clear();
         foreach (var (a, i) in _aspects.Select((a, i) => (a, i)))
@@ -902,6 +963,13 @@ public partial class QuickInputViewModel : ObservableObject
         ApplyRating(steps[Math.Clamp(idx + 1, 0, steps.Count - 1)]);
     }
 
+    /// Nutzer-Feedback: eine aus Versehen gesetzte Bewertung (z.B. Qualität, obwohl der Schüler
+    /// sich nie gemeldet hat) muss sich wieder auf "nicht bewertet" zurücksetzen lassen, ohne
+    /// einen inhaltlich falschen Wert stehen lassen zu müssen. Bewusst eine eigene Aktion statt
+    /// über 0/1 zu laufen — 0 ("--") ist bei Quantität ein echter, beobachteter Wert ("hat sich
+    /// nicht gemeldet"), kein Platzhalter für "nicht ermittelt".
+    public void ClearRating() => ApplyRating(null);
+
     public void DecrementRating()
     {
         var cell = GetCurrentCell();
@@ -918,7 +986,7 @@ public partial class QuickInputViewModel : ObservableObject
         ApplyRating(steps[Math.Clamp(idx - 1, 0, steps.Count - 1)]);
     }
 
-    private void ApplyRating(int val)
+    private void ApplyRating(int? val)
     {
         if (_rows.Count == 0 || !_aspects.Any()) return;
         var key = _aspects[Math.Clamp(AspectIndex, 0, _aspects.Count - 1)].Key;

LehrerApp.Desktop/ViewModels/Groups/ParticipationWizardViewModels.cs

@@ -20,6 +20,7 @@ public partial class ParticipationWizardDialogViewModel : ObservableObject
     private readonly IExamRepository _exams;
     private readonly IExamResultRepository _results;
     private readonly IGradeRepository _grades;
+    private readonly IUnitRepository _units;
     private readonly Dictionary<Guid, GroupMembership> _membershipsByStudent;
     private readonly GradingService _grading;
     private readonly Guid _groupId;
@@ -75,11 +76,11 @@ public partial class ParticipationWizardDialogViewModel : ObservableObject
         IParticipationAspectRepository aspects, IParticipationSectionRepository sectionRepo,
         IStudentRepository students, IGroupMembershipRepository memberships,
         IExamRepository exams, IExamResultRepository results,
-        IGradeRepository grades, GradingService grading,
+        IGradeRepository grades, IUnitRepository units, GradingService grading,
         Guid groupId, string schoolYear, GradingSystem gradingSystem, string groupLabel)
     {
         _sessions = sessions; _entries = entries; _sectionRepo = sectionRepo;
-        _exams = exams; _results = results; _grades = grades; _grading = grading;
+        _exams = exams; _results = results; _grades = grades; _units = units; _grading = grading;
         _groupId = groupId; _schoolYear = schoolYear; _gradingSystem = gradingSystem;
         GroupLabel = groupLabel;
         _membershipsByStudent = memberships.GetByGroup(groupId).ToDictionary(m => m.StudentId);
@@ -98,6 +99,7 @@ public partial class ParticipationWizardDialogViewModel : ObservableObject
 
         _rollupPeriod = RollupPeriodOptions[0];
         NewSectionLabel = $"Abschnitt {_sectionList.Count + 1}";
+        NewSectionEndDateText = SuggestSectionEndDate().ToString("dd.MM.yyyy");
 
         if (_students.Count > 0) ShowStudent(0);
     }
@@ -277,6 +279,23 @@ public partial class ParticipationWizardDialogViewModel : ObservableObject
         _sectionList.Count > 0 ? _sectionList.Max(s => s.EndDate).AddDays(1)
         : (_allSessions.Count > 0 ? _allSessions.Min(s => s.Date) : DateOnly.FromDateTime(DateTime.Today));
 
+    /// Schlägt als Abschnittsende bewusst nicht immer "heute" vor: Wenn seit Abschnittsbeginn
+    /// eine Unterrichtseinheit (4.2) abgeschlossen wurde, ist deren Ende meist die fachlich
+    /// sinnvollere Zäsur für eine Mitarbeit-Teilnote als das Bearbeitungsdatum im Wizard.
+    private DateOnly SuggestSectionEndDate()
+    {
+        var openStart = ComputeOpenStart();
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var completedUnitEnd = _units.GetByGroup(_groupId)
+            .Where(u => u.Status == UnitStatus.Completed && u.EndDate.HasValue)
+            .Select(u => u.EndDate!.Value)
+            .Where(d => d >= openStart && d <= today)
+            .OrderByDescending(d => d)
+            .Cast<DateOnly?>()
+            .FirstOrDefault();
+        return completedUnitEnd ?? today;
+    }
+
     private void BuildSections(Guid studentId)
     {
         Sections.Clear();
@@ -378,6 +397,7 @@ public partial class ParticipationWizardDialogViewModel : ObservableObject
         }
 
         NewSectionLabel = $"Abschnitt {_sectionList.Count + 1}";
+        NewSectionEndDateText = SuggestSectionEndDate().ToString("dd.MM.yyyy");
         BuildTimeline(CurrentStudentId);
         BuildSections(CurrentStudentId);
     }

LehrerApp.Desktop/ViewModels/Groups/PlanningViewModels.cs

@@ -13,7 +13,8 @@ namespace LehrerApp.Desktop.ViewModels.Groups;
 
 // ── Ergebnisse der Verschieben-/Kopieren-/Serienerzeugungs-Dialoge (4.2.4 / 4.1.4 / 4.2.5) ───
 
-public record MoveLessonTarget(DateOnly NewDate, bool ShiftFollowing);
+public record MoveLessonTarget(DateOnly NewDate, bool ShiftFollowing, int? NewPeriod = null,
+    bool SplitDoubleLesson = false);
 public record CopyUnitTarget(Guid TargetGroupId, DateOnly AnchorDate);
 
 public record LessonSeriesResult(int Created, int SkippedHoliday, int SkippedExisting)
@@ -78,6 +79,7 @@ public partial class PlanningTabViewModel : ObservableObject
     public Func<Unit, Task<LessonSeriesResult?>>? OnGenerateLessonSeries { get; set; }
     public Func<Unit, Task<bool>>? OnAiAssist { get; set; }
     public Action<string>? OnNotify { get; set; }
+    public Action<string>? OnError { get; set; }
 
     public PlanningTabViewModel(IUnitRepository units, ILessonRepository lessons,
         IGroupRepository groups, ISubjectRepository subjects,
@@ -333,7 +335,8 @@ public partial class PlanningTabViewModel : ObservableObject
         var lesson = SelectedLesson.Model;
         var target = await OnPickMoveTarget(lesson);
         if (target is null) return;
-        MoveLessonInternal(lesson, target.NewDate, target.ShiftFollowing);
+        try { MoveLessonInternal(lesson, target.NewDate, target.ShiftFollowing, target.NewPeriod); }
+        catch (InvalidOperationException ex) { OnError?.Invoke(ex.Message); return; }
         LoadUnits();
     }
 
@@ -341,33 +344,19 @@ public partial class PlanningTabViewModel : ObservableObject
     /// sich alle anderen noch geplanten Stunden derselben Einheit, die ursprünglich NACH der
     /// verschobenen Stunde lagen, um denselben Tages-Delta. Bereits durchgeführte Stunden werden
     /// nie angefasst — nur Date ändert sich, UnitId/GroupId bleiben unverändert.
-    private void MoveLessonInternal(Lesson moved, DateOnly newDate, bool shiftFollowing)
+    private void MoveLessonInternal(Lesson moved, DateOnly newDate, bool shiftFollowing, int? newPeriod = null)
     {
-        var oldDate = moved.Date;
+        new LessonSchedulingService(_lessons).Move(moved, newDate, newPeriod, shiftFollowing);
-        var delta = newDate.DayNumber - oldDate.DayNumber;
-
-        if (shiftFollowing && delta != 0)
-        {
-            foreach (var other in _lessons.GetByUnit(moved.UnitId))
-            {
-                if (other.Id == moved.Id) continue;
-                if (other.Status != LessonStatus.Planned) continue;
-                if (other.Date <= oldDate) continue;
-                other.Date = other.Date.AddDays(delta);
-                _lessons.Save(other);
-            }
-        }
-
-        moved.Date = newDate;
-        _lessons.Save(moved);
     }
 
     [RelayCommand(CanExecute = nameof(HasSelectedLesson))]
     private void AdvanceLessonStatus()
     {
-        if (SelectedLesson is null || SelectedLesson.Model.Status != LessonStatus.Planned) return;
+        if (SelectedLesson is null || SelectedLesson.Model.Status == LessonStatus.Conducted) return;
         var lesson = SelectedLesson.Model;
-        lesson.Status = LessonStatus.Conducted;
+        lesson.Status = lesson.Status == LessonStatus.Ready
+            ? LessonStatus.Conducted
+            : LessonStatus.Ready;
         _lessons.Save(lesson);
         LoadUnits();
     }
@@ -479,8 +468,14 @@ public class LessonSummary
         Topic = l.Topic;
         StartTimeDisplay = l.StartTime?.ToString("HH:mm") ?? "–";
         Status = l.Status;
-        StatusLabel = l.Status == LessonStatus.Conducted ? "Durchgeführt" : "Geplant";
+        StatusLabel = LessonStatusDisplay.ToName(l.Status);
-        StatusColorHex = l.Status == LessonStatus.Conducted ? "#43A047" : "#9E9E9E";
+        StatusColorHex = l.Status switch
+        {
+            LessonStatus.Draft => "#78909C",
+            LessonStatus.Ready => "#1976D2",
+            LessonStatus.Conducted => "#43A047",
+            _ => "#9E9E9E",
+        };
         PhaseCountLabel = l.Phases.Count == 0 ? "–" : $"{l.Phases.Count} Phasen";
         var totalMinutes = l.Phases.Sum(p => p.DurationMinutes);
         TotalDurationLabel = totalMinutes == 0 ? "–" : $"{totalMinutes} Min.";
@@ -515,12 +510,23 @@ public static class UnitStatusDisplay
 
 public static class LessonStatusDisplay
 {
-    public static string[] Options { get; } = ["Geplant", "Durchgeführt"];
+    public static string[] Options { get; } = ["Entwurf", "Geplant", "Bereit", "Durchgeführt"];
 
-    public static string ToName(LessonStatus s) => s == LessonStatus.Conducted ? "Durchgeführt" : "Geplant";
+    public static string ToName(LessonStatus s) => s switch
+    {
+        LessonStatus.Draft => "Entwurf",
+        LessonStatus.Ready => "Bereit",
+        LessonStatus.Conducted => "Durchgeführt",
+        _ => "Geplant",
+    };
 
-    public static LessonStatus FromName(string? name) =>
+    public static LessonStatus FromName(string? name) => name switch
-        name == "Durchgeführt" ? LessonStatus.Conducted : LessonStatus.Planned;
+    {
+        "Entwurf" => LessonStatus.Draft,
+        "Bereit" => LessonStatus.Ready,
+        "Durchgeführt" => LessonStatus.Conducted,
+        _ => LessonStatus.Planned,
+    };
 }
 
 // ── Dialog: Einheit anlegen / bearbeiten (4.1.2 / 4.1.3) ─────────────────────
@@ -722,7 +728,8 @@ public partial class LessonDialogViewModel : ObservableObject
         IAlternativeLessonPathRepository alternativePaths, ITimetableSlotRepository timetableSlots,
         PeriodScheduleService periodSchedule, IAttachmentStorage attachmentStorage,
         Guid unitId, Guid groupId, string groupName, string subjectName,
-        List<string> materialSuggestions, List<string> shorthandHistorySuggestions, Lesson? editingLesson)
+        List<string> materialSuggestions, List<string> shorthandHistorySuggestions, Lesson? editingLesson,
+        DateOnly? suggestedDate = null, int? suggestedPeriod = null)
     {
         _lessons = lessons; _alternativePaths = alternativePaths;
         _timetableSlots = timetableSlots; _periodSchedule = periodSchedule;
@@ -760,9 +767,12 @@ public partial class LessonDialogViewModel : ObservableObject
         }
         else
         {
-            var (date, lessonNumber) = SuggestNextLesson();
+            var (date, lessonNumber) = suggestedDate.HasValue
+                ? (suggestedDate.Value, suggestedPeriod)
+                : SuggestNextLesson();
             DateText = date.ToString("dd.MM.yyyy");
             LessonNumber = lessonNumber;
+            StatusName = LessonStatusDisplay.ToName(LessonStatus.Draft);
         }
         RecomputeTimes();
     }
@@ -1145,28 +1155,45 @@ public partial class AlternativePathDialogViewModel : ObservableObject
 public partial class MoveLessonDialogViewModel : ObservableObject
 {
     [ObservableProperty] private string _newDateText;
+    [ObservableProperty] private int? _newPeriod;
     [ObservableProperty] private bool _shiftFollowingPlanned = true;
+    [ObservableProperty] private bool _splitDoubleLesson;
     [ObservableProperty] private string _newDateTextError = "";
+    [ObservableProperty] private string _newPeriodError = "";
 
     public string CurrentDateDisplay { get; }
+    public string CurrentPeriodDisplay { get; }
+    public bool CanSplitDoubleLesson { get; }
     public MoveLessonTarget? Result { get; private set; }
 
-    public MoveLessonDialogViewModel(DateOnly currentDate)
+    public MoveLessonDialogViewModel(DateOnly currentDate, int? currentPeriod = null,
+        bool canSplitDoubleLesson = false, bool splitByDefault = false)
     {
         CurrentDateDisplay = currentDate.ToString("dd.MM.yyyy");
+        CurrentPeriodDisplay = currentPeriod is null ? "nicht festgelegt" : $"{currentPeriod}. Stunde";
         _newDateText = currentDate.ToString("dd.MM.yyyy");
+        _newPeriod = currentPeriod;
+        CanSplitDoubleLesson = canSplitDoubleLesson;
+        _splitDoubleLesson = canSplitDoubleLesson && splitByDefault;
     }
 
     [RelayCommand]
     private void Save()
     {
         NewDateTextError = "";
+        NewPeriodError = "";
         if (!DateOnly.TryParseExact(NewDateText, "dd.MM.yyyy", null, DateTimeStyles.None, out var date))
         {
             NewDateTextError = "Format TT.MM.JJJJ.";
             return;
         }
-        Result = new MoveLessonTarget(date, ShiftFollowingPlanned);
+        if (NewPeriod is < 1 or > 20)
+        {
+            NewPeriodError = "Bitte eine Stundennummer zwischen 1 und 20 wählen.";
+            return;
+        }
+        Result = new MoveLessonTarget(date, ShiftFollowingPlanned, NewPeriod,
+            CanSplitDoubleLesson && SplitDoubleLesson);
     }
 }
 

LehrerApp.Desktop/ViewModels/Groups/SeatingPlanViewModels.cs

@@ -93,14 +93,37 @@ public partial class SeatingPlanTabViewModel : ObservableObject
     /// Legt bei Bedarf die "Sitzung für heute" an, mit der Sitzplan-Bewertungen/-Markierungen
     /// verknüpft werden — aber erst, wenn tatsächlich etwas bewertet/markiert wird (AssessStudent/
     /// ToggleSituationTag), nicht schon beim Öffnen des Tabs.
+    ///
+    /// Prüft dabei bewusst gegen das Repository und nicht nur gegen das lokal geladene
+    /// <see cref="TodaySessions"/> / <see cref="SelectedSession"/>: Der Unterrichtsmodus
+    /// (<see cref="SelectOrCreateSessionForLesson"/>) läuft auf einer eigenen, per DI frisch
+    /// aufgelösten <see cref="SeatingPlanTabViewModel"/>-Instanz (siehe TimetableView.ShowTeachingMode),
+    /// getrennt von der Instanz, die im Sitzplan-Tab der Kursübersicht hängt. Eine dort bereits
+    /// heute angelegte (ggf. verknüpfte) Sitzung ist dieser Instanz also unbekannt, solange sie nur
+    /// im lokalen Feld nachschaut — das führte dazu, dass eine zweite, unverknüpfte "Sitzplan"-
+    /// Sitzung für denselben Tag entstand, sobald im echten Sitzplan-Tab bewertet wurde.
     private ParticipationSessionOption? EnsureTodaySession()
     {
         if (SelectedSession is not null) return SelectedSession;
         if (!IsEditable) return null;
 
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var existing = _sessions.GetByGroup(_groupId).FirstOrDefault(s => s.Date == today);
+        if (existing is not null)
+        {
+            var found = TodaySessions.FirstOrDefault(o => o.Id == existing.Id);
+            if (found is null)
+            {
+                found = new ParticipationSessionOption(existing);
+                TodaySessions.Add(found);
+            }
+            SelectedSession = found;
+            return found;
+        }
+
         var created = new ParticipationSession
         {
-            GroupId = _groupId, Date = DateOnly.FromDateTime(DateTime.Today), Comment = "Sitzplan",
+            GroupId = _groupId, Date = today, Comment = "Sitzplan",
         };
         _sessions.Save(created);
         var option = new ParticipationSessionOption(created);
@@ -204,7 +227,7 @@ public partial class SeatingPlanTabViewModel : ObservableObject
                       ?? StudentSeatOption.Empty;
                 var isHidden = hiddenSeats.Any(h => h.Row == row && h.Column == column);
                 Seats.Add(new SeatCellViewModel(row, column, StudentOptions, option, OnSeatChanged,
-                    CanEditLayout, ToggleSituationTag, IsEditable, isHidden, ToggleSeatHidden));
+                    CanEditLayout, ToggleSituationTag, IsEditable, isHidden, ToggleSeatHidden, TallyParticipation));
             }
             UpdateAssignmentSummary();
             RefreshSeatLessonData();
@@ -213,6 +236,13 @@ public partial class SeatingPlanTabViewModel : ObservableObject
         NotifyCommands();
     }
 
+    /// Öffentlich statt intern (kein InternalsVisibleTo in dieser Codebasis, siehe
+    /// UntisSyncService-Kommentar): der Unterrichtsmodus bewertet über eine zweite, unabhängige
+    /// ParticipationTabViewModel-Instanz (Schnellbewertungs-Dialoge, siehe TeachingModeWindow) —
+    /// diese Instanz hier bekommt davon nichts automatisch mit und muss nach jedem Dialog explizit
+    /// neu aus dem Repository laden, damit die Sitzplatz-Badges nicht veraltet bleiben.
+    public void ReloadSeatBadgesFromRepository() => RefreshSeatLessonData();
+
     private void RefreshSeatLessonData()
     {
         if (SelectedSession is null)
@@ -236,6 +266,22 @@ public partial class SeatingPlanTabViewModel : ObservableObject
         }
     }
 
+    /// Strichliste im Sitzplan (Nutzer-Feedback): "drangekommen" ist immer auch eine Meldung und
+    /// erhöht daher beide Zähler — es gibt kein "drangekommen, ohne sich gemeldet zu haben".
+    private void TallyParticipation(SeatCellViewModel seat, bool calledOn)
+    {
+        if (!IsEditable || seat.SelectedOption.StudentId is not Guid studentId) return;
+        var session = EnsureTodaySession();
+        if (session is null) return;
+
+        var entry = _participation.GetBySessionAndStudent(session.Id, studentId)
+            ?? new ParticipationEntry { SessionId = session.Id, StudentId = studentId };
+        entry.RaisedHandCount++;
+        if (calledOn) entry.CalledOnCount++;
+        _participation.Save(entry);
+        RefreshSeatLessonData();
+    }
+
     private void ToggleSituationTag(SeatCellViewModel seat, string tag)
     {
         if (!IsEditable || _documentation is null ||
@@ -501,9 +547,13 @@ public partial class SeatCellViewModel : ObservableObject
     [ObservableProperty] private double _lessonOpacity = 1.0;
     [ObservableProperty] private string _attendanceBadge = "";
     [ObservableProperty] private string _homeworkBadge = "";
+    [ObservableProperty] private string _dayHighlightBadge = "";
+    [ObservableProperty] private int _raisedHandCount;
+    [ObservableProperty] private int _calledOnCount;
     public ObservableCollection<SituationTagChoice> SituationTags { get; } = [];
     public bool HasAttendanceBadge => AttendanceBadge.Length > 0;
     public bool HasHomeworkBadge => HomeworkBadge.Length > 0;
+    public bool HasDayHighlightBadge => DayHighlightBadge.Length > 0;
     public bool ShowLessonOverview => IsOccupied && !CanEdit;
     [ObservableProperty] private bool _canRecordLesson;
     public bool IsOccupied => SelectedOption.StudentId.HasValue;
@@ -525,10 +575,13 @@ public partial class SeatCellViewModel : ObservableObject
     /// die Abblendung für ausgeblendete Plätze hier statt per CSS-Klasse erfolgen.</summary>
     public double DisplayOpacity => IsHidden ? 0.4 : LessonOpacity;
 
+    private readonly Action<SeatCellViewModel, bool> _tally;
+
     public SeatCellViewModel(int row, int column, ObservableCollection<StudentSeatOption> options,
         StudentSeatOption selectedOption, Action<SeatCellViewModel> onChanged, bool canEdit,
         Action<SeatCellViewModel, string>? toggleSituationTag = null, bool canRecordLesson = false,
-        bool isHidden = false, Action<SeatCellViewModel>? toggleHidden = null)
+        bool isHidden = false, Action<SeatCellViewModel>? toggleHidden = null,
+        Action<SeatCellViewModel, bool>? tally = null)
     {
         Row = row;
         Column = column;
@@ -540,10 +593,18 @@ public partial class SeatCellViewModel : ObservableObject
         _canRecordLesson = canRecordLesson;
         _isHidden = isHidden;
         _toggleHidden = toggleHidden ?? (_ => { });
+        _tally = tally ?? ((_, _) => { });
         foreach (var tag in SituationTagChoice.DefaultTags)
             SituationTags.Add(new SituationTagChoice(tag, false, value => _toggleSituationTag(this, value)));
     }
 
+    /// Strichliste im Sitzplan (Nutzer-Feedback): schnelles Mitzählen während des Unterrichts,
+    /// ohne dafür den vollen Sitzplatz-Bewertungsdialog öffnen zu müssen — bewusst nur ein
+    /// Hochzählen ohne Korrekturmöglichkeit hier direkt auf der Kachel; die Rohwerte bleiben über
+    /// den Bewertungsdialog einsehbar und fließen dort als Quantitäts-Vorschlag ein.
+    [RelayCommand] private void TallyRaisedHand() => _tally(this, false);
+    [RelayCommand] private void TallyCalledOn() => _tally(this, true);
+
     partial void OnSelectedOptionChanged(StudentSeatOption value)
     {
         OnPropertyChanged(nameof(IsOccupied));
@@ -585,12 +646,16 @@ public partial class SeatCellViewModel : ObservableObject
         var attendance = entry?.Attendance;
         AttendanceBadge = attendance is null ? "" : AttendanceDisplay.ShortLabel(attendance);
         HomeworkBadge = entry is null ? "" : HomeworkDisplay.Symbol(HomeworkDisplay.Effective(entry));
+        DayHighlightBadge = DayHighlightDisplay.Symbol(entry?.DayHighlight);
+        RaisedHandCount = entry?.RaisedHandCount ?? 0;
+        CalledOnCount = entry?.CalledOnCount ?? 0;
         LessonOpacity = attendance is not null and not AttendanceStatus.Present
             and not AttendanceStatus.Late and not AttendanceStatus.SignificantlyLate ? 0.42 : 1.0;
         var selected = tags.ToHashSet(StringComparer.OrdinalIgnoreCase);
         foreach (var choice in SituationTags) choice.IsSelected = selected.Contains(choice.Text);
         OnPropertyChanged(nameof(HasAttendanceBadge));
         OnPropertyChanged(nameof(HasHomeworkBadge));
+        OnPropertyChanged(nameof(HasDayHighlightBadge));
     }
 }
 
@@ -616,6 +681,7 @@ public partial class SeatAssessmentViewModel : ObservableObject
     [ObservableProperty] private int _selectedAspectIndex;
     [ObservableProperty] private string _attendanceLabel = "Noch nicht kontrolliert";
     [ObservableProperty] private string _homeworkLabel = "Keine Hausaufgabe aufgegeben";
+    [ObservableProperty] private string _dayHighlightLabel = "Keine Markierung";
 
     public string StudentName { get; }
     public string SessionDisplay { get; }
@@ -626,6 +692,7 @@ public partial class SeatAssessmentViewModel : ObservableObject
     public ObservableCollection<SeatAssessmentAspectRow> AspectRows { get; } = [];
     public ObservableCollection<SeatAttendanceChoice> AttendanceChoices { get; } = [];
     public ObservableCollection<SeatHomeworkChoice> HomeworkChoices { get; } = [];
+    public ObservableCollection<SeatDayHighlightChoice> DayHighlightChoices { get; } = [];
 
     public SeatAssessmentViewModel(IParticipationSessionRepository sessions,
         IParticipationRepository entries, IParticipationAspectRepository aspects,
@@ -660,11 +727,15 @@ public partial class SeatAssessmentViewModel : ObservableObject
         foreach (var (aspect, index) in aspectDefinitions.Select((a, i) => (a, i)))
         {
             var value = _entry?.Ratings.FirstOrDefault(r => r.Key == aspect.Key)?.Value;
-            AspectRows.Add(new SeatAssessmentAspectRow(index, aspect, value, ApplyRating));
+            // Quantitäts-Vorschlag aus der Sitzplan-Strichliste (Nutzer-Feedback): nur für den
+            // eingebauten "quantity"-Aspekt, siehe ParticipationCountSuggestion.
+            var raisedHandCount = aspect.Key == "quantity" ? _entry?.RaisedHandCount : null;
+            AspectRows.Add(new SeatAssessmentAspectRow(index, aspect, value, ApplyRating, raisedHandCount));
         }
 
         BuildAttendanceChoices();
         BuildHomeworkChoices();
+        BuildDayHighlightChoices();
         RefreshStatusChoices();
         SelectAspect(0);
     }
@@ -697,6 +768,17 @@ public partial class SeatAssessmentViewModel : ObservableObject
         HomeworkChoices.Add(new("·", "Keine aufgegeben", "⌥X", null, SetHomework));
     }
 
+    private void BuildDayHighlightChoices()
+    {
+        DayHighlightChoices.Add(new(DayHighlightDisplay.Symbol(DayHighlightKind.Standout),
+            DayHighlightDisplay.Label(DayHighlightKind.Standout), "⇧1", DayHighlightKind.Standout, SetDayHighlight));
+        DayHighlightChoices.Add(new(DayHighlightDisplay.Symbol(DayHighlightKind.Sleepy),
+            DayHighlightDisplay.Label(DayHighlightKind.Sleepy), "⇧2", DayHighlightKind.Sleepy, SetDayHighlight));
+        DayHighlightChoices.Add(new(DayHighlightDisplay.Symbol(DayHighlightKind.Rough),
+            DayHighlightDisplay.Label(DayHighlightKind.Rough), "⇧3", DayHighlightKind.Rough, SetDayHighlight));
+        DayHighlightChoices.Add(new("·", "Keine Markierung", "⇧X", null, SetDayHighlight));
+    }
+
     public void SelectAspect(int index)
     {
         if (index < 0 || index >= AspectRows.Count) return;
@@ -763,6 +845,17 @@ public partial class SeatAssessmentViewModel : ObservableObject
         if (clear || digit is 0 or 1 or 3 or 4 or 5 or 7 or 8) SetHomework(status);
     }
 
+    public void ApplyDayHighlightShortcut(int? digit, bool clear)
+    {
+        if (!CanEdit) return;
+        var kind = clear ? null : digit switch
+        {
+            1 => DayHighlightKind.Standout, 2 => DayHighlightKind.Sleepy, 3 => DayHighlightKind.Rough,
+            _ => (DayHighlightKind?)null,
+        };
+        if (clear || digit is 1 or 2 or 3) SetDayHighlight(kind);
+    }
+
     private void ApplyRating(string key, int? value)
     {
         if (!CanEdit || _entry is null) return;
@@ -793,13 +886,23 @@ public partial class SeatAssessmentViewModel : ObservableObject
         RefreshStatusChoices();
     }
 
+    private void SetDayHighlight(DayHighlightKind? kind)
+    {
+        if (!CanEdit || _entry is null) return;
+        _entry.DayHighlight = kind;
+        _entries.Save(_entry);
+        RefreshStatusChoices();
+    }
+
     private void RefreshStatusChoices()
     {
         AttendanceLabel = AttendanceDisplay.Label(_entry?.Attendance);
         HomeworkLabel = HomeworkDisplay.Label(_entry is null ? null : HomeworkDisplay.Effective(_entry));
+        DayHighlightLabel = DayHighlightDisplay.Label(_entry?.DayHighlight);
         foreach (var choice in AttendanceChoices) choice.IsSelected = choice.Status == _entry?.Attendance;
         var homework = _entry is null ? null : HomeworkDisplay.Effective(_entry);
         foreach (var choice in HomeworkChoices) choice.IsSelected = choice.Status == homework;
+        foreach (var choice in DayHighlightChoices) choice.IsSelected = choice.Kind == _entry?.DayHighlight;
     }
 }
 
@@ -817,11 +920,22 @@ public partial class SeatAssessmentAspectRow : ObservableObject
     public string DisplayValue => ParticipationRatingScale.DisplayLabel(ValueType, Value);
     public ObservableCollection<SeatRatingChoice> Choices { get; } = [];
 
+    /// Quantitäts-Vorschlag aus der Sitzplan-Strichliste (Nutzer-Feedback), siehe
+    /// ParticipationCountSuggestion — null, wenn keine Strichliste zu diesem Aspekt gehört.
+    private readonly int? _raisedHandCount;
+    public int? SuggestedValue { get; }
+    public bool HasSuggestion => SuggestedValue.HasValue && SuggestedValue != Value;
+    public string SuggestionLabel =>
+        $"{_raisedHandCount}× gemeldet → Vorschlag: {ParticipationRatingScale.DisplayLabel(ValueType, SuggestedValue)}";
+
     public SeatAssessmentAspectRow(int index, ParticipationAspect aspect, int? value,
-        Action<string, int?> apply)
+        Action<string, int?> apply, int? raisedHandCount = null)
     {
         Index = index; Key = aspect.Key; Label = aspect.Label; ValueType = aspect.ValueType;
         MaxPoints = aspect.MaxPoints; _value = value; _apply = apply;
+        _raisedHandCount = raisedHandCount;
+        SuggestedValue = raisedHandCount is int rhc
+            ? ParticipationCountSuggestion.SuggestQuantity(ValueType, rhc) : null;
         var steps = ValueType == AspectValueType.Points
             ? Enumerable.Range(0, Math.Min(MaxPoints, 9) + 1).Select(v => (v, v.ToString())).ToList()
             : ParticipationRatingScale.Steps(ValueType).ToList();
@@ -834,10 +948,13 @@ public partial class SeatAssessmentAspectRow : ObservableObject
     {
         Value = value;
         OnPropertyChanged(nameof(DisplayValue));
+        OnPropertyChanged(nameof(HasSuggestion));
         foreach (var choice in Choices) choice.IsSelected = choice.Value == value;
         _apply(Key, value);
     }
 
+    [RelayCommand] private void ApplySuggestion() => ApplyValue(SuggestedValue);
+
     public void Adjust(int delta)
     {
         if (ValueType == AspectValueType.Points)
@@ -888,6 +1005,17 @@ public partial class SeatHomeworkChoice(string symbol, string label, string shor
     [RelayCommand] private void Apply() => apply(Status);
 }
 
+public partial class SeatDayHighlightChoice(string symbol, string label, string shortcut,
+    DayHighlightKind? kind, Action<DayHighlightKind?> apply) : ObservableObject
+{
+    public string Symbol { get; } = symbol;
+    public string Label { get; } = label;
+    public string Shortcut { get; } = shortcut;
+    public DayHighlightKind? Kind { get; } = kind;
+    [ObservableProperty] private bool _isSelected;
+    [RelayCommand] private void Apply() => apply(Kind);
+}
+
 public partial class SeatingPlanDialogViewModel : ObservableObject
 {
     private readonly ISeatingPlanRepository _plans;

LehrerApp.Desktop/ViewModels/Groups/StudentPerformanceOverviewViewModel.cs

@@ -0,0 +1,310 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Desktop.ViewModels.Students;
+using System.Collections.ObjectModel;
+using System.Globalization;
+
+namespace LehrerApp.Desktop.ViewModels.Groups;
+
+// ── Schüler-Leistungsüberblick + Zielnoten-Rechner (Nutzer-Feedback) ─────────────
+//
+// Zeigt die Leistungen eines einzelnen Schülers in einem Kurs im Überblick — Klausuren,
+// Mitarbeit- und sonstige Noten, die daraus berechnete Zeugnisnote sowie zwei Rechner
+// ("Zielnote": was brauche ich noch? / "Was-wäre-wenn": wie wirkt sich eine zusätzliche
+// Klausurnote aus?). Bewusst pro Kurs statt fächerübergreifend, da Gewichtungsschema und
+// Notensystem am Kurs hängen. Zwei Modi über IsTeacherMode: im Bewertermodus zusätzlich
+// Kursdurchschnitt je Klausur und Bearbeitbarkeit der Mitarbeit-/Sonstige-Noten; im
+// Schülermodus ausschließlich die eigenen Werte, rein lesend — gedacht, um den Bildschirm im
+// Gespräch umzudrehen. Exam-Noten bleiben bewusst nur lesbar: eine Korrektur läuft weiterhin
+// über den bestehenden ExamGradingDialog, der die Punkte-Struktur konsistent hält — direktes
+// Überschreiben von Exam.Grade hier könnte mit ExamResult.Points/TotalPoints auseinanderlaufen.
+public partial class StudentPerformanceOverviewViewModel : ObservableObject
+{
+    private readonly IGradeRepository _grades;
+    private readonly IExamRepository _exams;
+    private readonly IExamResultRepository _results;
+    private readonly IGroupMembershipRepository _memberships;
+    private readonly IGradingSchemeRepository _schemes;
+    private readonly GradingService _grading;
+
+    private readonly Guid _groupId;
+    private readonly Guid _studentId;
+    private readonly GroupType _groupType;
+    private readonly GradingSystem _gradingSystem;
+    private readonly string _schoolYear;
+
+    private GradingScheme _scheme = new();
+    private double? _examsAverage;
+    private double? _participationAverage;
+    private double? _otherAverage;
+    private List<(string Grade, double Weight)> _examGradesRaw = [];
+    private List<(string Grade, double Weight)> _participationGradesRaw = [];
+    private List<(string Grade, double Weight)> _otherGradesRaw = [];
+
+    public string StudentName { get; }
+    public string GroupLabel { get; }
+
+    [ObservableProperty] private ParticipationPeriodOption _selectedPeriod;
+    [ObservableProperty] private bool _isTeacherMode = true;
+    [ObservableProperty] private string _schemeSummary = "";
+    [ObservableProperty] private string? _examsAverageDisplay;
+    [ObservableProperty] private string? _participationAverageDisplay;
+    [ObservableProperty] private string? _otherAverageDisplay;
+    [ObservableProperty] private string _currentReportGradeDisplay = "";
+
+    [ObservableProperty] private string _targetGradeText = "";
+    [ObservableProperty] private GradeBucketKind _targetBucket = GradeBucketKind.Exams;
+    [ObservableProperty] private string _targetResultDisplay = "";
+
+    [ObservableProperty] private string _whatIfExamGradeText = "";
+    [ObservableProperty] private string _whatIfResultDisplay = "";
+
+    public List<ParticipationPeriodOption> PeriodOptions { get; } =
+    [
+        new(ParticipationPeriod.FullYear, "Gesamtes Schuljahr"),
+        new(ParticipationPeriod.H1, "1. Halbjahr"),
+        new(ParticipationPeriod.H2, "2. Halbjahr"),
+    ];
+
+    public string[] TargetBucketOptions { get; } = ["Klausuren", "Mitarbeit", "Sonstige"];
+
+    public string TargetBucketName
+    {
+        get => TargetBucket switch
+        {
+            GradeBucketKind.Participation => "Mitarbeit",
+            GradeBucketKind.Other => "Sonstige",
+            _ => "Klausuren",
+        };
+        set => TargetBucket = value switch
+        {
+            "Mitarbeit" => GradeBucketKind.Participation,
+            "Sonstige" => GradeBucketKind.Other,
+            _ => GradeBucketKind.Exams,
+        };
+    }
+
+    public ObservableCollection<StudentExamRow> ExamRows { get; } = [];
+    /// Eigener Verlauf (Nutzer-Feedback): dieselbe Balken-Sparkline wie die bestehende
+    /// Notenentwicklung im Schülerdetail (2.5), hier nur auf die Klausuren dieses Kurses
+    /// beschränkt statt aller Lerngruppen — passt zum Kursdurchschnitt-Vergleich je Klausur.
+    public StudentGradeHistoryGroup ExamHistory { get; } = new("Klausurverlauf");
+    public ObservableCollection<StudentSimpleGradeRow> ParticipationRows { get; } = [];
+    public ObservableCollection<StudentSimpleGradeRow> OtherRows { get; } = [];
+
+    public StudentPerformanceOverviewViewModel(IGradeRepository grades, IExamRepository exams,
+        IExamResultRepository results, IGroupMembershipRepository memberships,
+        IGradingSchemeRepository schemes, GradingService grading,
+        Guid groupId, Guid studentId, GroupType groupType, GradingSystem gradingSystem,
+        string studentName, string groupLabel, string schoolYear)
+    {
+        _grades = grades; _exams = exams; _results = results; _memberships = memberships;
+        _schemes = schemes; _grading = grading;
+        _groupId = groupId; _studentId = studentId; _groupType = groupType;
+        _gradingSystem = gradingSystem; _schoolYear = schoolYear;
+        StudentName = studentName; GroupLabel = groupLabel;
+
+        _selectedPeriod = PeriodOptions[0];
+        Recompute();
+    }
+
+    partial void OnSelectedPeriodChanged(ParticipationPeriodOption value) => Recompute();
+
+    public string ModeButtonLabel => IsTeacherMode ? "Modus: Bewerter" : "Modus: Schüler";
+
+    partial void OnIsTeacherModeChanged(bool value) => OnPropertyChanged(nameof(ModeButtonLabel));
+
+    [RelayCommand]
+    private void ToggleMode() => IsTeacherMode = !IsTeacherMode;
+
+    private GradingScheme ResolveScheme() =>
+        _schemes.GetByGroup(_groupId)
+        ?? _schemes.GetDefaultForType(_groupType)
+        ?? new GradingScheme { ExamsPercent = 50, ParticipationPercent = 40, OtherPercent = 10 };
+
+    private void Recompute()
+    {
+        _scheme = ResolveScheme();
+        SchemeSummary = $"Klausuren {_scheme.ExamsPercent:0.#} % · Mitarbeit {_scheme.ParticipationPercent:0.#} % · " +
+                         $"Sonstige {_scheme.OtherPercent:0.#} %";
+
+        var (periodFrom, periodTo) = GroupMembershipService.SchoolYearPeriod(_schoolYear, SelectedPeriod.Period switch
+        {
+            ParticipationPeriod.H1 => SchoolYearPeriodKind.H1,
+            ParticipationPeriod.H2 => SchoolYearPeriodKind.H2,
+            _ => SchoolYearPeriodKind.FullYear,
+        });
+        var membership = _memberships.GetByGroup(_groupId).FirstOrDefault(m => m.StudentId == _studentId);
+
+        // ── Klausuren ─────────────────────────────────────────────────────
+        ExamRows.Clear();
+        ExamHistory.Points.Clear();
+        _examGradesRaw = [];
+        int? previousNoteEquivalent = null;
+        foreach (var exam in _exams.GetByGroup(_groupId)
+                     .Where(e => e.Date >= periodFrom && e.Date <= periodTo)
+                     .Where(e => membership is null || GroupMembershipService.IsActiveOn(membership, e.Date))
+                     .Where(e => !e.Niveau.HasValue || membership?.Niveau == e.Niveau)
+                     .OrderBy(e => e.Date))
+        {
+            var allResults = _results.GetByExam(exam.Id);
+            var own = allResults.FirstOrDefault(r => r.StudentId == _studentId);
+            string? ownGrade = own is { Absent: false, Grade: not null } ? own.Grade : null;
+            if (ownGrade is not null) _examGradesRaw.Add((ownGrade, 1.0));
+
+            var classGrades = allResults.Where(r => !r.Absent && r.Grade is not null)
+                .Select(r => (r.Grade!, 1.0)).ToList();
+            var classAverage = classGrades.Count > 0 ? _grading.WeightedAverage(classGrades) : (double?)null;
+
+            ExamRows.Add(new StudentExamRow(exam.Title, exam.Date, ownGrade,
+                classAverage.HasValue ? FormatGrade(classAverage.Value) : "–"));
+
+            // Gleiche Balken-Sparkline wie die bestehende Notenentwicklung (2.5): Rohwert auf die
+            // 1..6-Notenäquivalent-Achse abbilden, damit Grades1To6 und Points0To15 dieselbe
+            // Balkenhöhen-Formel nutzen können.
+            int? noteEquivalent = ownGrade is not null && int.TryParse(ownGrade, out var raw)
+                ? (_gradingSystem == GradingSystem.Grades1To6 ? raw : int.Parse(PointsNoteMapping.PointsToNote(raw)))
+                : null;
+            var isFailing = noteEquivalent is >= 5;
+            var isDrop = noteEquivalent.HasValue && previousNoteEquivalent.HasValue
+                         && noteEquivalent.Value - previousNoteEquivalent.Value >= 1;
+            var warnings = new List<string>();
+            if (isDrop) warnings.Add("Abfall um ≥ 1 Note");
+            if (isFailing) warnings.Add("Versetzungsgefährdung");
+            ExamHistory.Points.Add(new GradeHistoryPoint(exam.Date, exam.Title, ownGrade ?? "–",
+                noteEquivalent, warnings.Count > 0, string.Join(" · ", warnings)));
+            if (noteEquivalent.HasValue) previousNoteEquivalent = noteEquivalent;
+        }
+        _examsAverage = _examGradesRaw.Count > 0 ? _grading.WeightedAverage(_examGradesRaw) : null;
+
+        // ── Mitarbeit & Sonstige ──────────────────────────────────────────
+        var allGrades = _grades.GetByStudentAndGroup(_studentId, _groupId)
+            .Where(g => g.Date >= periodFrom && g.Date <= periodTo)
+            .Where(g => membership is null || GroupMembershipService.IsActiveOn(membership, g.Date))
+            .OrderBy(g => g.Date).ToList();
+
+        ParticipationRows.Clear();
+        _participationGradesRaw = [];
+        foreach (var g in allGrades.Where(g => g.Category == GradeCategory.Participation))
+        {
+            _participationGradesRaw.Add((g.Value, g.Weight));
+            ParticipationRows.Add(new StudentSimpleGradeRow(g, SaveGrade));
+        }
+        _participationAverage = _participationGradesRaw.Count > 0 ? _grading.WeightedAverage(_participationGradesRaw) : null;
+
+        OtherRows.Clear();
+        _otherGradesRaw = [];
+        foreach (var g in allGrades.Where(g => g.Category != GradeCategory.Participation))
+        {
+            _otherGradesRaw.Add((g.Value, g.Weight));
+            OtherRows.Add(new StudentSimpleGradeRow(g, SaveGrade));
+        }
+        _otherAverage = _otherGradesRaw.Count > 0 ? _grading.WeightedAverage(_otherGradesRaw) : null;
+
+        ExamsAverageDisplay = _examsAverage.HasValue ? FormatGrade(_examsAverage.Value) : null;
+        ParticipationAverageDisplay = _participationAverage.HasValue ? FormatGrade(_participationAverage.Value) : null;
+        OtherAverageDisplay = _otherAverage.HasValue ? FormatGrade(_otherAverage.Value) : null;
+
+        var reportGrade = _grading.CalculateReportGrade(_examGradesRaw, _participationGradesRaw, _otherGradesRaw,
+            _scheme, _gradingSystem, RoundingRule.Commercial);
+        CurrentReportGradeDisplay = reportGrade is null
+            ? "Noch nicht berechenbar — keine Werte im gewählten Zeitraum."
+            : $"Note {reportGrade}";
+
+        RecomputeTarget();
+        RecomputeWhatIf();
+    }
+
+    private void SaveGrade(Grade grade)
+    {
+        _grades.Save(grade);
+        Recompute();
+    }
+
+    partial void OnTargetGradeTextChanged(string value) => RecomputeTarget();
+    partial void OnTargetBucketChanged(GradeBucketKind value)
+    {
+        OnPropertyChanged(nameof(TargetBucketName));
+        RecomputeTarget();
+    }
+
+    private void RecomputeTarget()
+    {
+        if (!TryParseGrade(TargetGradeText, out var target))
+        {
+            TargetResultDisplay = "";
+            return;
+        }
+
+        var result = ReportGradeTargetCalculator.SolveRequiredAverage(target, TargetBucket,
+            _examsAverage, _participationAverage, _otherAverage, _scheme, _gradingSystem);
+
+        TargetResultDisplay = result switch
+        {
+            null => $"{TargetBucketName} fließt laut Gewichtungsschema nicht in die Zeugnisnote ein.",
+            { IsAchievable: true } r => $"Nötiger Schnitt in {TargetBucketName}: {FormatGrade(r.RequiredAverage)}",
+            { IsAchievable: false } r =>
+                $"Mit den übrigen Bereichen rechnerisch nicht mehr erreichbar (bräuchte {FormatGrade(r.RequiredAverage)}).",
+        };
+    }
+
+    partial void OnWhatIfExamGradeTextChanged(string value) => RecomputeWhatIf();
+
+    private void RecomputeWhatIf()
+    {
+        if (string.IsNullOrWhiteSpace(WhatIfExamGradeText))
+        {
+            WhatIfResultDisplay = "";
+            return;
+        }
+
+        var hypothetical = new List<(string Grade, double Weight)>(_examGradesRaw) { (WhatIfExamGradeText.Trim(), 1.0) };
+        var result = _grading.CalculateReportGrade(hypothetical, _participationGradesRaw, _otherGradesRaw,
+            _scheme, _gradingSystem, RoundingRule.Commercial);
+        WhatIfResultDisplay = result is null
+            ? "Ungültige Note."
+            : $"Zeugnisnote mit dieser zusätzlichen Klausurnote: {result}";
+    }
+
+    private static bool TryParseGrade(string text, out double value) =>
+        double.TryParse(text.Trim().Replace(',', '.'), NumberStyles.Float, CultureInfo.InvariantCulture, out value);
+
+    private static string FormatGrade(double value) => value.ToString("0.0", CultureInfo.InvariantCulture);
+}
+
+public class StudentExamRow(string title, DateOnly date, string? ownGrade, string classAverageDisplay)
+{
+    public string Title { get; } = title;
+    public string DateDisplay { get; } = date.ToString("dd.MM.yyyy");
+    public string OwnGradeDisplay { get; } = ownGrade ?? "–";
+    public string ClassAverageDisplay { get; } = classAverageDisplay;
+}
+
+public partial class StudentSimpleGradeRow : ObservableObject
+{
+    private readonly Grade _grade;
+    private readonly Action<Grade> _save;
+
+    public string CategoryLabel { get; }
+    public string DateDisplay { get; }
+    [ObservableProperty] private string _value;
+
+    public StudentSimpleGradeRow(Grade grade, Action<Grade> save)
+    {
+        _grade = grade;
+        _save = save;
+        CategoryLabel = GradeCategoryDisplay.Label(grade.Category);
+        DateDisplay = grade.Date.ToString("dd.MM.yyyy");
+        _value = grade.Value;
+    }
+
+    [RelayCommand]
+    private void Save()
+    {
+        _grade.Value = Value.Trim();
+        _save(_grade);
+    }
+}

LehrerApp.Desktop/ViewModels/Groups/TeachingModeViewModel.cs

@@ -1,3 +1,5 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
 using LehrerApp.Core.Interfaces;
 using LehrerApp.Core.Models;
 
@@ -10,24 +12,104 @@ namespace LehrerApp.Desktop.ViewModels.Groups;
 /// der "Heute"-Tagesliste heraus gestartet.
 ///
 /// Bewusst keine eigene DI-Registrierung als Singleton/Transient: wie LessonViewerViewModel wird
-/// diese ViewModel direkt vom Code-Behind konstruiert, das dafür nötige SeatingPlanTabViewModel
+/// diese ViewModel direkt vom Code-Behind konstruiert, das dafür nötige SeatingPlanTabViewModel/
-/// aber weiterhin über DI aufgelöst (transient, siehe AppBootstrapper) und hier per Konstruktor
+/// ParticipationTabViewModel aber weiterhin über DI aufgelöst (transient, siehe AppBootstrapper)
-/// entgegengenommen statt selbst aus App.Services zu ziehen - ViewModels greifen in diesem Code
+/// und hier per Konstruktor entgegengenommen statt selbst aus App.Services zu ziehen -
-/// nicht selbst auf den Service-Container zu, das bleibt Aufgabe des Code-Behind.
+/// ViewModels greifen in diesem Code nicht selbst auf den Service-Container zu, das bleibt
+/// Aufgabe des Code-Behind.
 /// </summary>
 public class TeachingModeViewModel
 {
     public string GroupName { get; }
     public LessonViewerViewModel LessonInfo { get; }
     public SeatingPlanTabViewModel SeatingPlan { get; }
+    /// <summary>Nutzer-Feedback: die Schnellbewertungs-Dialoge für Mitarbeit/Anwesenheit-Hausaufgabe
+    /// gab es bislang nur über den Mitarbeit-Tab der Gruppe — im Unterrichtsmodus musste man dafür
+    /// erst wieder raus. Hier dieselbe <see cref="ParticipationTabViewModel"/> wie im Mitarbeit-Tab,
+    /// aber auf die zu dieser Stunde gehörende Sitzung vorselektiert (siehe Konstruktor), damit die
+    /// über <c>OnQuickInput</c>/<c>OnStatusQuickInput</c> geöffneten Dialoge (Wiring in
+    /// TeachingModeWindow.axaml.cs, gleiches Muster wie ParticipationTabView.axaml.cs) direkt auf
+    /// der richtigen Sitzung starten.</summary>
+    public ParticipationTabViewModel Participation { get; }
+    public TeachingModeHomeworkViewModel Homework { get; }
 
     public TeachingModeViewModel(Lesson lesson, LearningGroup group,
-        IAlternativeLessonPathRepository alternativePaths, SeatingPlanTabViewModel seatingPlan)
+        IAlternativeLessonPathRepository alternativePaths, ILessonRepository lessons,
+        SeatingPlanTabViewModel seatingPlan, ParticipationTabViewModel participation)
     {
         GroupName = group.Name;
         LessonInfo = new LessonViewerViewModel(lesson, alternativePaths);
+
         SeatingPlan = seatingPlan;
         SeatingPlan.Initialize(group.Id, !group.IsActive);
         SeatingPlan.SelectOrCreateSessionForLesson(lesson);
+
+        Participation = participation;
+        Participation.Initialize(group.Id, group.SchoolYear, !group.IsActive);
+        if (SeatingPlan.SelectedSession is { } linkedSession)
+            Participation.SelectedSession =
+                Participation.Sessions.FirstOrDefault(s => s.Id == linkedSession.Id);
+
+        // 4.5.4: dieselbe "letzte Stunde vor dieser"-Suche wie das Stundenplan-Badge
+        // "Hausaufgabe kontrollieren" (TimetableViewModel.HasUnhandledHomework) - 120 Tage
+        // Lookback deckt auch längere Ferienpausen ab, ohne unbegrenzt weit zurückzuscannen.
+        var previousLesson = lessons.GetByGroupAndRange(group.Id, lesson.Date.AddDays(-120), lesson.Date.AddDays(-1))
+            .OrderByDescending(l => l.Date).ThenByDescending(l => l.LessonNumber ?? 0)
+            .FirstOrDefault();
+        Homework = new TeachingModeHomeworkViewModel(lesson, previousLesson, lessons);
+    }
+}
+
+/// <summary>
+/// Nutzer-Feedback: im Unterrichtsmodus sollte man die Hausaufgabe aus der letzten Stunde als
+/// kontrolliert abhaken und die neue Hausaufgabe eintragen/ändern können, ohne dafür den vollen
+/// <see cref="LehrerApp.Desktop.Views.Groups.LessonDialog"/>-Editor zu öffnen (der zusätzlich Phasen/Reflexion usw. zeigt)
+/// - manchmal ergibt sich die Hausaufgabe erst während der Stunde. Bewusst eine eigene, kleine
+/// <see cref="ObservableObject"/> statt Felder direkt auf <see cref="TeachingModeViewModel"/>, da
+/// diese Klasse (wie <see cref="LessonViewerViewModel"/>) selbst keine Bindable-Basisklasse hat.
+/// </summary>
+public partial class TeachingModeHomeworkViewModel : ObservableObject
+{
+    private readonly ILessonRepository _lessons;
+    private readonly Lesson _lesson;
+    private readonly Lesson? _previousLesson;
+
+    public bool HasPreviousHomework =>
+        _previousLesson is not null && !string.IsNullOrWhiteSpace(_previousLesson.Homework);
+    public string PreviousHomeworkText => _previousLesson?.Homework ?? "";
+    public string PreviousLessonLabel => _previousLesson is null ? "" :
+        $"{_previousLesson.Date:dd.MM.yyyy}" + (string.IsNullOrWhiteSpace(_previousLesson.Topic)
+            ? "" : $" · {_previousLesson.Topic}");
+
+    [ObservableProperty] private bool _previousHomeworkChecked;
+    [ObservableProperty] private string _currentHomework;
+    [ObservableProperty] private string _saveStatus = "";
+
+    public TeachingModeHomeworkViewModel(Lesson lesson, Lesson? previousLesson, ILessonRepository lessons)
+    {
+        _lesson = lesson;
+        _previousLesson = previousLesson;
+        _lessons = lessons;
+        _previousHomeworkChecked = previousLesson?.HomeworkChecked ?? false;
+        _currentHomework = lesson.Homework ?? "";
+    }
+
+    /// Sofort beim Umschalten gespeichert (kein separater Speichern-Klick nötig) - dieselbe
+    /// Checkbox-Semantik wie im LessonDialog (4.5.4): "kontrolliert" und "nicht kontrollieren"
+    /// schließen sich aus.
+    partial void OnPreviousHomeworkCheckedChanged(bool value)
+    {
+        if (_previousLesson is null) return;
+        _previousLesson.HomeworkChecked = value;
+        if (value) _previousLesson.HomeworkCheckDismissed = false;
+        _lessons.Save(_previousLesson);
+    }
+
+    [RelayCommand]
+    private void SaveCurrentHomework()
+    {
+        _lesson.Homework = CurrentHomework;
+        _lessons.Save(_lesson);
+        SaveStatus = "Gespeichert.";
     }
 }

LehrerApp.Desktop/ViewModels/Groups/WebUntisClassSelectionViewModel.cs

@@ -0,0 +1,56 @@
+using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Desktop.Services;
+
+namespace LehrerApp.Desktop.ViewModels.Groups;
+
+public partial class WebUntisClassSelectionViewModel(WebUntisIntegrationService untis) : ObservableObject
+{
+    public ObservableCollection<UntisSchoolYearDto> SchoolYears { get; } = [];
+    public ObservableCollection<UntisClassDto> Classes { get; } = [];
+    [ObservableProperty] private UntisSchoolYearDto? _selectedSchoolYear;
+    [ObservableProperty] private UntisClassDto? _selectedClass;
+    [ObservableProperty] private string _status = "";
+    [ObservableProperty] private bool _busy;
+    public bool CanConfirm => SelectedClass is not null && !Busy;
+
+    partial void OnSelectedClassChanged(UntisClassDto? value) => OnPropertyChanged(nameof(CanConfirm));
+    partial void OnBusyChanged(bool value) => OnPropertyChanged(nameof(CanConfirm));
+
+    public async Task InitializeAsync()
+    {
+        Busy = true;
+        try
+        {
+            foreach (var year in (await untis.GetSchoolYearsAsync()).OrderByDescending(x => x.StartDate))
+                SchoolYears.Add(year);
+            SelectedSchoolYear = SchoolYears.FirstOrDefault(x => x.StartDate <= Today() && x.EndDate >= Today())
+                                 ?? SchoolYears.FirstOrDefault();
+            await LoadClasses();
+        }
+        catch (WebUntisIntegrationException ex) { Status = ex.Message; }
+        finally { Busy = false; }
+    }
+
+    [RelayCommand]
+    private async Task LoadClasses()
+    {
+        if (SelectedSchoolYear is null) return;
+        Busy = true; Classes.Clear(); SelectedClass = null;
+        try
+        {
+            foreach (var entry in (await untis.GetClassesAsync(SelectedSchoolYear.UntisId)).OrderBy(x => x.Name))
+                Classes.Add(entry);
+            Status = Classes.Count == 0 ? "Keine Klassen gefunden." : $"{Classes.Count} Klassen gefunden.";
+        }
+        catch (WebUntisIntegrationException ex) { Status = ex.Message; }
+        finally { Busy = false; }
+    }
+
+    private static int Today()
+    {
+        var date = DateOnly.FromDateTime(DateTime.Today);
+        return date.Year * 10000 + date.Month * 100 + date.Day;
+    }
+}

LehrerApp.Desktop/ViewModels/Groups/WebUntisLessonAbsenceComparisonViewModel.cs

@@ -0,0 +1,238 @@
+using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Importing;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Desktop.Services;
+
+namespace LehrerApp.Desktop.ViewModels.Groups;
+
+/// <summary>Eine Zeile bleibt auch ohne automatische Zuordnung sichtbar (statt stillschweigend
+/// weggefiltert zu werden) - <see cref="AssignedStudent"/> kann manuell per Auswahlliste gesetzt
+/// werden, wenn weder `ENr` noch der Name eindeutig auf ein Kursmitglied passen.</summary>
+public partial class WebUntisLessonAbsenceRow : ObservableObject
+{
+    public required string UntisStudentName { get; init; }
+    public required DateOnly Date { get; init; }
+    public required string TimeLabel { get; init; }
+    public required string UntisStatus { get; init; }
+    public required AttendanceStatus TargetStatus { get; init; }
+    public required IReadOnlyList<Student> Candidates { get; init; }
+    internal Action<WebUntisLessonAbsenceRow>? OnAssignmentChanged { get; init; }
+    public string? Reason { get; init; }
+    public string DateLabel => Date.ToString("dd.MM.yyyy");
+    public bool CanApply => SessionId is not null;
+
+    [ObservableProperty] private Student? _assignedStudent;
+    [ObservableProperty] private string _localStatus = "ohne Zuordnung";
+    [ObservableProperty] private Guid? _sessionId;
+    [ObservableProperty] private bool _selected;
+
+    partial void OnAssignedStudentChanged(Student? value) => OnAssignmentChanged?.Invoke(this);
+}
+
+/// <summary>Fehlzeitenabgleich über den "Fehlzeiten pro Unterricht"-Bericht (<see cref="LearningGroup.WebUntisLessonId"/>).
+/// Der früher genutzte, pro Schüler abgerufene Fehlzeiten-Report (getTimetableWithAbsences) brauchte
+/// weitergehende WebUntis-Rechte als dieser Lerngruppen-Bericht und wurde deshalb entfernt.</summary>
+public partial class WebUntisLessonAbsenceComparisonViewModel : ObservableObject
+{
+    private readonly LearningGroup _group;
+    private readonly WebUntisIntegrationService _untis;
+    private readonly IStudentRepository _students;
+    private readonly IParticipationSessionRepository _sessions;
+    private readonly IParticipationRepository _participation;
+
+    private IReadOnlyList<Student> _loadedStudents = [];
+    private IReadOnlyDictionary<DateOnly, ParticipationSession> _loadedSessions =
+        new Dictionary<DateOnly, ParticipationSession>();
+
+    public ObservableCollection<WebUntisLessonAbsenceRow> Rows { get; } = [];
+    [ObservableProperty] private DateTimeOffset _startDate = DateTimeOffset.Now.AddMonths(-2);
+    [ObservableProperty] private DateTimeOffset _endDate = DateTimeOffset.Now;
+    [ObservableProperty] private string _status = "Zeitraum wählen und Fehlzeiten laden.";
+    [ObservableProperty] private bool _busy;
+    [ObservableProperty] private bool _markUnknownAsPresent;
+
+    public WebUntisLessonAbsenceComparisonViewModel(LearningGroup group, WebUntisIntegrationService untis,
+        IStudentRepository students, IParticipationSessionRepository sessions,
+        IParticipationRepository participation)
+    {
+        _group = group; _untis = untis; _students = students; _sessions = sessions;
+        _participation = participation;
+    }
+
+    [RelayCommand]
+    private async Task Load()
+    {
+        var lessonId = _group.WebUntisLessonId;
+        if (lessonId is null)
+        {
+            Status = "Für diese Lerngruppe ist noch keine WebUntis-Unterrichtsnummer hinterlegt " +
+                     "(Gruppe bearbeiten).";
+            return;
+        }
+
+        var start = DateOnly.FromDateTime(StartDate.LocalDateTime);
+        var end = DateOnly.FromDateTime(EndDate.LocalDateTime);
+        if (end < start) { Status = "Das Enddatum darf nicht vor dem Startdatum liegen."; return; }
+        Busy = true; Rows.Clear();
+        try
+        {
+            var courseStudents = _students.GetByGroup(_group.Id);
+            var localSessions = _sessions.GetByGroup(_group.Id)
+                .Where(x => x.Date >= start && x.Date <= end).GroupBy(x => x.Date)
+                .ToDictionary(x => x.Key, x => x.First());
+            _loadedStudents = courseStudents;
+            _loadedSessions = localSessions;
+            // Erste Wahl: WebUntis-Kennung (ENr). Nicht jeder Schüler hat eine (z.B. manuell statt
+            // per WebUntis-Import angelegt) - Fallback über den Namen, aber nur wenn er innerhalb
+            // der Kursmitglieder eindeutig ist, sonst lieber unzugeordnet lassen als raten.
+            var byKey = courseStudents.Select(student => (Student: student, Key: StudentKey(student)))
+                .Where(x => x.Key is not null).ToDictionary(x => x.Key!.Value, x => x.Student);
+            var byName = courseStudents
+                .SelectMany(student => new[]
+                {
+                    NameKey($"{student.LastName} {student.FirstName}"),
+                    NameKey($"{student.FirstName} {student.LastName}"),
+                }.Select(key => (Key: key, Student: student)))
+                .GroupBy(x => x.Key)
+                .Where(group => group.Select(x => x.Student).Distinct().Count() == 1)
+                .ToDictionary(group => group.Key, group => group.First().Student);
+
+            var absences = await _untis.GetLessonAbsencesAsync(lessonId.Value, start, end);
+            var ordered = absences
+                .Select(absence => (Absence: absence, Date: TryDate(absence.Date, out var date) ? date : (DateOnly?)null))
+                .Where(x => x.Date is not null)
+                .OrderBy(x => x.Date).ThenBy(x => x.Absence.StudentName);
+
+            void ResolveLocalMatch(WebUntisLessonAbsenceRow row)
+            {
+                if (row.AssignedStudent is not { } student)
+                {
+                    row.SessionId = null; row.LocalStatus = "ohne Zuordnung"; row.Selected = false;
+                    return;
+                }
+                localSessions.TryGetValue(row.Date, out var session);
+                var entry = session is null ? null : _participation.GetBySessionAndStudent(session.Id, student.Id);
+                row.SessionId = session?.Id;
+                row.LocalStatus = session is null ? "keine lokale Stunde" : AttendanceDisplay.Label(entry?.Attendance);
+                row.Selected = session is not null && entry?.Attendance != row.TargetStatus;
+            }
+
+            foreach (var (absence, date) in ordered)
+            {
+                var match = absence.ExternKey is { } key && byKey.TryGetValue(key, out var byKeyStudent)
+                    ? byKeyStudent
+                    : byName.GetValueOrDefault(NameKey(absence.StudentName));
+                var row = new WebUntisLessonAbsenceRow
+                {
+                    UntisStudentName = absence.StudentName, Date = date!.Value,
+                    TimeLabel = TimeLabel(absence.StartTime, absence.EndTime),
+                    UntisStatus = DisplayUntisStatus(absence),
+                    TargetStatus = MapStatus(absence), Reason = absence.Reason,
+                    Candidates = courseStudents, OnAssignmentChanged = ResolveLocalMatch,
+                };
+                Rows.Add(row);
+                row.AssignedStudent = match; // löst OnAssignedStudentChanged aus und setzt SessionId/LocalStatus/Selected
+            }
+
+            var unresolved = Rows.Count(x => x.AssignedStudent is null);
+            Status = $"{absences.Count} Fehlzeiten von WebUntis erhalten, {Rows.Count - unresolved} automatisch zugeordnet" +
+                     (unresolved > 0 ? $", {unresolved} bitte manuell zuordnen" : "") +
+                     $". {Rows.Count(x => x.CanApply)} sind einer lokalen Kursstunde zuordenbar.";
+        }
+        catch (WebUntisIntegrationException ex) { Status = ex.Message; }
+        finally { Busy = false; }
+    }
+
+    [RelayCommand]
+    private void Apply()
+    {
+        var selected = Rows.Where(x => x.Selected && x.SessionId is not null && x.AssignedStudent is not null).ToList();
+        foreach (var row in selected)
+        {
+            var studentId = row.AssignedStudent!.Id;
+            var entry = _participation.GetBySessionAndStudent(row.SessionId!.Value, studentId)
+                        ?? new ParticipationEntry { SessionId = row.SessionId.Value, StudentId = studentId };
+            entry.Attendance = row.TargetStatus;
+            entry.UpdatedAt = DateTime.UtcNow;
+            _participation.Save(entry);
+        }
+
+        var presentCount = MarkUnknownAsPresent ? FillUnknownAsPresent() : 0;
+        Status = $"{selected.Count} Anwesenheitsstatus übernommen." +
+                 (MarkUnknownAsPresent ? $" {presentCount} unbekannte Status auf anwesend gesetzt." : "");
+        foreach (var row in selected) row.Selected = false;
+    }
+
+    // "Identifiziert" heißt hier: WebUntis hat für diesen Schüler an diesem Tag überhaupt eine Zeile
+    // gemeldet - unabhängig davon, ob die Zeile markiert/übernommen wurde. Nur wer für den geladenen
+    // Zeitraum weder von WebUntis gemeldet noch lokal schon kontrolliert wurde, gilt als "unbekannt"
+    // und wird auf anwesend gesetzt; bereits erfasste Einträge (auch ohne Anwesenheitsstatus, z.B. nur
+    // mit Notiz) werden nicht überschrieben, wenn ihr Anwesenheitsstatus schon gesetzt ist.
+    private int FillUnknownAsPresent()
+    {
+        var identified = Rows.Where(x => x.AssignedStudent is not null)
+            .Select(x => (x.Date, StudentId: x.AssignedStudent!.Id))
+            .ToHashSet();
+        var filled = 0;
+        foreach (var session in _loadedSessions.Values)
+        foreach (var student in _loadedStudents)
+        {
+            if (identified.Contains((session.Date, student.Id))) continue;
+            var entry = _participation.GetBySessionAndStudent(session.Id, student.Id);
+            if (entry?.Attendance is not null) continue;
+            entry ??= new ParticipationEntry { SessionId = session.Id, StudentId = student.Id };
+            entry.Attendance = AttendanceStatus.Present;
+            entry.UpdatedAt = DateTime.UtcNow;
+            _participation.Save(entry);
+            filled++;
+        }
+        return filled;
+    }
+
+    private static int? StudentKey(Student student)
+    {
+        student.ExternalIds ??= [];
+        return student.ExternalIds.TryGetValue(StudentImportFormats.MasterDataCsv.Value, out var value)
+               && int.TryParse(value, out var key) ? key : null;
+    }
+
+    // Groß-/Kleinschreibung, Leerraum und - da die tatsächliche WebUntis-Reihenfolge nicht
+    // dokumentiert und schulabhängig unterschiedlich beobachtet wurde - beide Namensreihenfolgen
+    // werden beim Aufbau von `byName` registriert; hier wird nur normalisiert.
+    private static string NameKey(string value) => value.Trim().ToLowerInvariant();
+
+    private const int FullLessonMinutes = 45;
+
+    // Der Bericht liefert keinen Entschuldigungstext, nur Minutenwerte, ein Bearbeitet-Datum und die
+    // (laut Schule) über Klammerung der ENr codierte Entscheidung des Klassenlehrers - ENr in
+    // Klammern bedeutet unentschuldigt, ohne Klammern abgeschlossen/entschuldigt. Reihenfolge ist
+    // wichtig: "nach Hause entlassen" zählt immer als vorzeitige Entlassung, unabhängig von der
+    // Dauer; darunter zählt jede Fehlzeit unter einer vollen Stunde (45 Min.) immer als Verspätung
+    // oder sonstiger Teilverlust, nie als komplette Abwesenheit - der Text "Verspätung" allein ist
+    // laut Schule nicht zuverlässig genug, deshalb primär über die Minutenschwelle erkannt.
+    private static AttendanceStatus MapStatus(UntisLessonAbsenceDto absence)
+    {
+        if (IsEarlyRelease(absence)) return AttendanceStatus.LeftDuringClass;
+        if (absence.AbsentMinutes < FullLessonMinutes) return AttendanceStatus.Late;
+        if (string.IsNullOrWhiteSpace(absence.HandledOn)) return AttendanceStatus.ExcusePending;
+        if (absence.ExternKey is null) return AttendanceStatus.ExcusePending;
+        return absence.ExternKeyInParentheses ? AttendanceStatus.Unexcused : AttendanceStatus.Excused;
+    }
+
+    private static bool IsEarlyRelease(UntisLessonAbsenceDto absence) =>
+        absence.Reason?.Contains("entlassen", StringComparison.OrdinalIgnoreCase) == true;
+
+    // Nutzt dieselben deutschen Bezeichnungen wie die reguläre Mitarbeitserfassung
+    // (AttendanceDisplay.Label), statt eigene Statustexte zu erfinden.
+    private static string DisplayUntisStatus(UntisLessonAbsenceDto absence) =>
+        string.Join(" · ", new[] { AttendanceDisplay.Label(MapStatus(absence)), absence.Reason }
+            .Where(x => !string.IsNullOrWhiteSpace(x)));
+
+    private static bool TryDate(int value, out DateOnly date) => DateOnly.TryParseExact(value.ToString(), "yyyyMMdd", out date);
+    private static string TimeLabel(int? start, int? end) =>
+        start is null || end is null ? "" : $"{Time(start.Value)}–{Time(end.Value)}";
+    private static string Time(int value) => $"{value / 100:00}:{value % 100:00}";
+}

LehrerApp.Desktop/ViewModels/MainWindowViewModel.cs

@@ -3,6 +3,8 @@ using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
 using LehrerApp.Core.Services;
 using LehrerApp.Desktop.Services;
+using LehrerApp.Desktop.ViewModels.ClassTeacher;
+using LehrerApp.Desktop.ViewModels.Exams;
 using LehrerApp.Desktop.ViewModels.Groups;
 using LehrerApp.Desktop.ViewModels.Planning;
 using LehrerApp.Desktop.ViewModels.Settings;
@@ -20,10 +22,12 @@ public partial class MainWindowViewModel : ObservableObject
     [ObservableProperty] private ObservableObject? _currentPage;
     [ObservableProperty] private NavItem _activeNavItem = NavItem.Dashboard;
     [ObservableProperty] private string _currentSchoolYear = "";
+    [ObservableProperty] private bool _isCommandPaletteOpen;
 
     public SyncStatusViewModel SyncStatus { get; }
     public ObservableCollection<ToastItem> Toasts { get; }
     public AppLockViewModel AppLock { get; }
+    public GlobalSearchViewModel CommandPalette { get; }
 
     public bool IsDashboardActive => ActiveNavItem == NavItem.Dashboard;
     public bool IsGroupsActive    => ActiveNavItem == NavItem.Groups;
@@ -31,22 +35,37 @@ public partial class MainWindowViewModel : ObservableObject
     public bool IsExamsActive     => ActiveNavItem == NavItem.Exams;
     public bool IsPlannerActive   => ActiveNavItem == NavItem.Planner;
     public bool IsWorkloadActive  => ActiveNavItem == NavItem.Workload;
+    public bool IsClassTeacherActive => ActiveNavItem == NavItem.ClassTeacher;
     public bool IsSettingsActive  => ActiveNavItem == NavItem.Settings;
 
     public MainWindowViewModel(IServiceProvider services,
         DashboardViewModel dashboard, SchoolYearService sy,
-        SyncStatusViewModel syncStatus, NotificationService notifications, AppLockViewModel appLock)
+        SyncStatusViewModel syncStatus, NotificationService notifications, AppLockViewModel appLock,
+        GlobalSearchViewModel commandPalette)
     {
         _services         = services;
         SyncStatus        = syncStatus;
         Toasts            = notifications.Toasts;
         AppLock           = appLock;
+        CommandPalette    = commandPalette;
+        CommandPalette.OnClose = CloseCommandPalette;
         CurrentSchoolYear = sy.CurrentSchoolYear();
         CurrentPage       = dashboard;
         AppLock.ApplyConfig();
         SyncStatus.DataChanged += OnSyncDataChanged;
     }
 
+    [RelayCommand]
+    private void OpenCommandPalette()
+    {
+        if (AppLock.IsLocked) return;
+        CommandPalette.Reset();
+        IsCommandPaletteOpen = true;
+    }
+
+    [RelayCommand]
+    private void CloseCommandPalette() => IsCommandPaletteOpen = false;
+
     // EventApplier schreibt bei eingehenden Sync-Ereignissen absichtlich direkt auf die rohe
     // LiteDB-Collection, an jedem ViewModel vorbei (Ping-Pong-Vermeidung, siehe EventApplier-
     // Klassenkommentar) - ohne diesen Hook blieb die gerade sichtbare Seite bis zum nächsten
@@ -71,6 +90,8 @@ public partial class MainWindowViewModel : ObservableObject
             case TimetableViewModel vm: vm.Load(); break;
             case WorkloadViewModel vm:
                 vm.Tasks.Load(); vm.TimeTracking.Load(); vm.Evaluation.Load(); break;
+            case ClassTeacherOverviewViewModel vm: vm.LoadCommand.Execute(null); break;
+            case ExamsOverviewViewModel vm: vm.LoadCommand.Execute(null); break;
             case GroupDetailViewModel { Group: { } group } vm: vm.LoadGroup(group.Id); break;
             // Inline-Bearbeitung (IsEditing) nicht überschreiben - anders als die Gruppenansicht
             // laufen Namens-/Geschlechtsänderungen hier nicht über einen Dialog.
@@ -87,6 +108,7 @@ public partial class MainWindowViewModel : ObservableObject
         OnPropertyChanged(nameof(IsExamsActive));
         OnPropertyChanged(nameof(IsPlannerActive));
         OnPropertyChanged(nameof(IsWorkloadActive));
+        OnPropertyChanged(nameof(IsClassTeacherActive));
         OnPropertyChanged(nameof(IsSettingsActive));
     }
 
@@ -99,9 +121,10 @@ public partial class MainWindowViewModel : ObservableObject
             NavItem.Dashboard => GetDashboard(),
             NavItem.Groups    => _services.GetRequiredService<GroupListViewModel>(),
             NavItem.Students  => GetStudents(),
-            NavItem.Exams     => new PlaceholderViewModel { Title = "Klausuren", Icon = "📝" },
+            NavItem.Exams     => GetExams(),
             NavItem.Planner   => GetTimetable(),
             NavItem.Workload  => GetWorkload(),
+            NavItem.ClassTeacher => GetClassTeacherOverview(),
             NavItem.Settings  => _services.GetRequiredService<SettingsViewModel>(),
             _                 => CurrentPage,
         };
@@ -141,6 +164,22 @@ public partial class MainWindowViewModel : ObservableObject
         return workload;
     }
 
+    private ExamsOverviewViewModel GetExams()
+    {
+        var exams = _services.GetRequiredService<ExamsOverviewViewModel>();
+        exams.LoadCommand.Execute(null);
+        return exams;
+    }
+
+    private ClassTeacherOverviewViewModel GetClassTeacherOverview()
+    {
+        var vm = _services.GetRequiredService<ClassTeacherOverviewViewModel>();
+        vm.OnNavigateToSettings = () => { NavigateToSettings(SettingsTab.WebUntis); return Task.CompletedTask; };
+        vm.OnNavigateToWorkload = () => { NavigateToWorkload(); return Task.CompletedTask; };
+        vm.LoadCommand.Execute(null);
+        return vm;
+    }
+
     public void NavigateToGroupDetail(Guid groupId, int initialTab = 0)
     {
         ActiveNavItem     = NavItem.Groups;
@@ -175,7 +214,7 @@ public partial class MainWindowViewModel : ObservableObject
     public void NavigateToWorkload() => NavigateTo(NavItem.Workload);
 }
 
-public enum NavItem { Dashboard, Groups, Students, Exams, Planner, Workload, Settings }
+public enum NavItem { Dashboard, Groups, Students, Exams, Planner, Workload, ClassTeacher, Settings }
 
 public partial class PlaceholderViewModel : ObservableObject
 {

LehrerApp.Desktop/ViewModels/Planning/SchoolDayWeatherSummary.cs

@@ -0,0 +1,169 @@
+using LehrerApp.Core.Models;
+
+namespace LehrerApp.Desktop.ViewModels.Planning;
+
+public enum SchoolDayWeatherKind { Sunny, Cloudy, Rain, Storm, Thunderstorm }
+
+/// <summary>Verdichtet die stündliche MOSMIX-Prognose auf ein planungsrelevantes Schultagsymbol.
+/// Extremere Bedingungen haben bewusst Vorrang vor Mittelwerten.</summary>
+public sealed class SchoolDayWeatherSummary
+{
+    public DateOnly Date { get; init; }
+    public SchoolDayWeatherKind Kind { get; init; }
+    public double? MinTemperatureC { get; init; }
+    public double? MaxTemperatureC { get; init; }
+    public double PrecipitationMm { get; init; }
+    public double? MaxHourlyPrecipitationProbabilityPercent { get; init; }
+    public double? SunshineDurationHours { get; init; }
+    public double? MaxWindGustKmh { get; init; }
+    public IReadOnlyList<WeatherWarning> Warnings { get; init; } = [];
+
+    public string Symbol => Kind switch
+    {
+        SchoolDayWeatherKind.Thunderstorm => "⛈️",
+        SchoolDayWeatherKind.Storm => "💨",
+        SchoolDayWeatherKind.Rain => "🌧️",
+        SchoolDayWeatherKind.Cloudy => "☁️",
+        _ => "☀️",
+    };
+
+    public string Label => Kind switch
+    {
+        SchoolDayWeatherKind.Thunderstorm => "Gewitter",
+        SchoolDayWeatherKind.Storm => "Sturm",
+        SchoolDayWeatherKind.Rain => "Regen",
+        SchoolDayWeatherKind.Cloudy => "Bewölkt",
+        _ => "Sonnig",
+    };
+
+    public string Tooltip
+    {
+        get
+        {
+            var lines = new List<string> { $"{Label} · 08–16 Uhr" };
+            if (MinTemperatureC is { } min && MaxTemperatureC is { } max)
+                lines.Add("Temperatur: " + (Math.Abs(max - min) < 0.05
+                    ? $"{min:0.#} °C" : $"{min:0.#}–{max:0.#} °C"));
+            if (MaxHourlyPrecipitationProbabilityPercent is { } probability)
+                lines.Add($"Regenwahrscheinlichkeit: bis {probability:0} % (stündlich)");
+            if (PrecipitationMm >= 0.05) lines.Add($"Niederschlag: {PrecipitationMm:0.#} mm");
+            if (SunshineDurationHours is { } sunshine)
+                lines.Add($"Sonnenschein: {sunshine:0.#} h");
+            if (MaxWindGustKmh is { } gust) lines.Add($"Max. Böen: {gust:0.#} km/h");
+            foreach (var warning in Warnings)
+            {
+                var period = WarningPeriod(warning);
+                lines.Add($"⚠ {warning.Headline}{(period.Length > 0 ? $" ({period})" : "")}");
+                if (!string.IsNullOrWhiteSpace(warning.Instruction)) lines.Add(warning.Instruction.Trim());
+            }
+            return string.Join("\n", lines);
+        }
+    }
+
+    public static SchoolDayWeatherSummary? From(WeatherSnapshot snapshot, DateOnly date)
+    {
+        var allHours = snapshot.Forecast
+            .Where(x => DateOnly.FromDateTime(Local(x.ValidAt)) == date)
+            .ToList();
+        // Für die Unterrichtsplanung zählt vor allem der Zeitraum, in dem Schule stattfindet.
+        // Falls MOSMIX für diesen Zeitraum noch keine Werte liefert, bleibt der Tagesrest nutzbar.
+        var schoolHours = allHours.Where(x =>
+        {
+            var hour = Local(x.ValidAt).Hour;
+            return hour >= 8 && hour <= 16;
+        }).ToList();
+        var hours = schoolHours.Count > 0 ? schoolHours : allHours;
+        if (hours.Count == 0) return null;
+
+        var warnings = snapshot.Warnings.Where(x => WarningTouchesDate(x, date)).ToList();
+        var codes = hours.Where(x => x.WeatherCode.HasValue).Select(x => x.WeatherCode!.Value).ToList();
+        var precipitation = hours.Sum(x => x.PrecipitationMm ?? 0);
+        var probabilities = hours.Where(x => x.PrecipitationProbabilityPercent.HasValue)
+            .Select(x => x.PrecipitationProbabilityPercent!.Value).ToList();
+        var sunshineMinutes = hours.Where(x => x.SunshineDurationMinutes.HasValue)
+            .Select(x => x.SunshineDurationMinutes!.Value).ToList();
+        var gust = hours.Where(x => x.WindGustKmh.HasValue).Select(x => x.WindGustKmh!.Value).DefaultIfEmpty().Max();
+        var hasGust = hours.Any(x => x.WindGustKmh.HasValue);
+        var warningText = string.Join(" ", warnings.SelectMany(x => new[] { x.Event, x.Headline }));
+
+        var kind = codes.Any(x => x is >= 95 and <= 99) ||
+                   warningText.Contains("GEWITTER", StringComparison.OrdinalIgnoreCase)
+            ? SchoolDayWeatherKind.Thunderstorm
+            : (hasGust && gust >= 62) || ContainsStormWarning(warningText)
+                ? SchoolDayWeatherKind.Storm
+                : precipitation >= 0.2 || codes.Any(IsRainCode)
+                    ? SchoolDayWeatherKind.Rain
+                    : IsCloudy(hours, codes)
+                        ? SchoolDayWeatherKind.Cloudy
+                        : SchoolDayWeatherKind.Sunny;
+
+        var temperatures = hours.Where(x => x.TemperatureC.HasValue)
+            .Select(x => x.TemperatureC!.Value).ToList();
+        return new SchoolDayWeatherSummary
+        {
+            Date = date,
+            Kind = kind,
+            MinTemperatureC = temperatures.Count > 0 ? temperatures.Min() : null,
+            MaxTemperatureC = temperatures.Count > 0 ? temperatures.Max() : null,
+            PrecipitationMm = Math.Round(precipitation, 1, MidpointRounding.AwayFromZero),
+            MaxHourlyPrecipitationProbabilityPercent = probabilities.Count > 0
+                ? Math.Round(probabilities.Max(), 0, MidpointRounding.AwayFromZero) : null,
+            SunshineDurationHours = sunshineMinutes.Count > 0
+                ? Math.Round(sunshineMinutes.Sum() / 60, 1, MidpointRounding.AwayFromZero) : null,
+            MaxWindGustKmh = hasGust ? Math.Round(gust, 1, MidpointRounding.AwayFromZero) : null,
+            Warnings = warnings,
+        };
+    }
+
+    public static bool WarningTouchesDate(WeatherWarning warning, DateOnly date)
+    {
+        if (warning.Onset is null && warning.Expires is null) return false;
+        var start = warning.Onset is { } onset ? Local(onset) : Local(warning.Expires!.Value).AddHours(-12);
+        var end = warning.Expires is { } expires ? Local(expires) : start.AddHours(12);
+        var dayStart = date.ToDateTime(TimeOnly.MinValue);
+        var dayEnd = date.ToDateTime(TimeOnly.MaxValue);
+        return start <= dayEnd && end >= dayStart;
+    }
+
+    public static string WarningPeriod(WeatherWarning warning)
+    {
+        var onset = warning.Onset is { } start ? Local(start) : (DateTime?)null;
+        var expires = warning.Expires is { } end ? Local(end) : (DateTime?)null;
+        return (onset, expires) switch
+        {
+            ({ } a, { } b) when DateOnly.FromDateTime(a) == DateOnly.FromDateTime(b) =>
+                $"{a:dd.MM., HH:mm}–{b:HH:mm} Uhr",
+            ({ } a, { } b) => $"{a:dd.MM., HH:mm}–{b:dd.MM., HH:mm} Uhr",
+            ({ } a, null) => $"ab {a:dd.MM., HH:mm} Uhr",
+            (null, { } b) => $"bis {b:dd.MM., HH:mm} Uhr",
+            _ => "",
+        };
+    }
+
+    private static bool IsRainCode(int code) => code is >= 51 and <= 67 or >= 80 and <= 82;
+
+    private static bool IsCloudy(IEnumerable<WeatherForecastHour> hours, IEnumerable<int> codes)
+    {
+        var cloudValues = hours.Where(x => x.CloudCoverPercent.HasValue)
+            .Select(x => x.CloudCoverPercent!.Value).ToList();
+        return codes.Any(x => x is 2 or 3 or 45 or 48) ||
+               cloudValues.Count > 0 && cloudValues.Average() >= 60;
+    }
+
+    private static bool ContainsStormWarning(string text) =>
+        text.Contains("STURM", StringComparison.OrdinalIgnoreCase) ||
+        text.Contains("ORKAN", StringComparison.OrdinalIgnoreCase) ||
+        text.Contains("WIND", StringComparison.OrdinalIgnoreCase) ||
+        text.Contains("BÖEN", StringComparison.OrdinalIgnoreCase);
+
+    private static DateTime Local(DateTime value) => value.Kind == DateTimeKind.Utc
+        ? value.ToLocalTime() : value;
+}
+
+public sealed class WeekWeatherWarningItem(WeatherWarning warning)
+{
+    public string Headline { get; } = string.IsNullOrWhiteSpace(warning.Headline) ? warning.Event : warning.Headline;
+    public string PeriodDisplay { get; } = SchoolDayWeatherSummary.WarningPeriod(warning);
+    public string Tooltip { get; } = string.Join("\n", new[] { warning.Description, warning.Instruction }
+        .Where(x => !string.IsNullOrWhiteSpace(x)));
+}

LehrerApp.Desktop/ViewModels/Planning/TimetableLessonWorkflowViewModels.cs

@@ -0,0 +1,83 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using System.Collections.ObjectModel;
+
+namespace LehrerApp.Desktop.ViewModels.Planning;
+
+public sealed class TimetableUnitOption(Unit unit)
+{
+    public Unit Model { get; } = unit;
+    public string Label { get; } = unit.Title;
+    public string Detail { get; } = unit.Status switch
+    {
+        UnitStatus.Active => "Laufende Einheit",
+        UnitStatus.Completed => "Abgeschlossene Einheit",
+        _ => "Geplante Einheit",
+    };
+}
+
+/// <summary>Ordnet eine direkt aus dem Stundenplan angelegte Stunde einer Einheit zu.</summary>
+public partial class TimetableUnitPickerViewModel : ObservableObject
+{
+    private readonly IUnitRepository _units;
+    private readonly Guid _groupId;
+    private readonly DateOnly _date;
+
+    public string ContextLabel { get; }
+    public ObservableCollection<TimetableUnitOption> Units { get; } = [];
+    [ObservableProperty] private TimetableUnitOption? _selectedUnit;
+    [ObservableProperty] private string _newUnitTitle = "";
+    [ObservableProperty] private string _error = "";
+    public Unit? Result { get; private set; }
+    public bool ResultIsNew { get; private set; }
+    public bool HasUnits => Units.Count > 0;
+
+    public TimetableUnitPickerViewModel(IUnitRepository units, Guid groupId, string groupName,
+        DateOnly date, int period)
+    {
+        _units = units;
+        _groupId = groupId;
+        _date = date;
+        ContextLabel = $"{groupName} · {date:dd.MM.yyyy} · {period}. Stunde";
+
+        foreach (var unit in units.GetByGroup(groupId)
+                     .OrderBy(u => u.Status == UnitStatus.Active ? 0 : u.Status == UnitStatus.Planned ? 1 : 2)
+                     .ThenByDescending(u => u.StartDate)
+                     .ThenBy(u => u.Title, StringComparer.CurrentCultureIgnoreCase))
+            Units.Add(new TimetableUnitOption(unit));
+        SelectedUnit = Units.FirstOrDefault();
+    }
+
+    [RelayCommand]
+    private void Save()
+    {
+        Error = "";
+        if (!string.IsNullOrWhiteSpace(NewUnitTitle))
+        {
+            Result = new Unit
+            {
+                GroupId = _groupId,
+                Title = NewUnitTitle.Trim(),
+                StartDate = _date,
+                Status = UnitStatus.Active,
+            };
+            // Erst speichern, wenn auch der anschließende Stunden-Dialog bestätigt wurde. So
+            // hinterlässt ein Abbruch keine leere Einheit.
+            ResultIsNew = true;
+            return;
+        }
+
+        if (SelectedUnit is null)
+        {
+            Error = "Bitte eine Einheit auswählen oder eine neue benennen.";
+            return;
+        }
+        Result = SelectedUnit.Model;
+        ResultIsNew = false;
+    }
+}
+
+public sealed record TimetableLessonRequest(Guid GroupId, DateOnly Date, int PeriodNumber);
+public sealed record TimetableLessonMoveRequest(Lesson Lesson, int SelectedPeriod);

LehrerApp.Desktop/ViewModels/Planning/TimetableViewModel.cs

@@ -5,6 +5,7 @@ using LehrerApp.Core.Models;
 using LehrerApp.Core.Services;
 using LehrerApp.Desktop.Services;
 using LehrerApp.Desktop.ViewModels.Settings;
+using LehrerApp.Desktop.ViewModels.Groups;
 using System.Collections.ObjectModel;
 
 namespace LehrerApp.Desktop.ViewModels.Planning;
@@ -65,6 +66,10 @@ public partial class TimetableViewModel : ObservableObject
     private readonly ISubstitutionEntryRepository _substitutions;
     private readonly IUntisSlotMappingRepository _untisMappings;
     private readonly WebUntisSettingsService _untisSettings;
+    private readonly PeriodScheduleService _periodSchedule;
+    private readonly SchoolWeatherService? _schoolWeather;
+    private readonly SemaphoreSlim _weatherGate = new(1, 1);
+    private WeatherSnapshot? _weatherSnapshot;
 
     public ObservableCollection<TimetableCellItem> Cells { get; } = [];
     public ObservableCollection<WeekCellItem> WeekItems { get; } = [];
@@ -73,6 +78,7 @@ public partial class TimetableViewModel : ObservableObject
     public ObservableCollection<TodaySupervisionItem> TodaySupervisions { get; } = [];
     public ObservableCollection<TodaySpecialAssignmentItem> TodaySpecialAssignments { get; } = [];
     public ObservableCollection<UpcomingExamItem> UpcomingExams { get; } = [];
+    public ObservableCollection<WeekWeatherWarningItem> WeekWeatherWarnings { get; } = [];
 
     /// Cells/WeekItems zeilenweise gruppiert (GridColumns Zellen je Zeile), zusätzlich zur
     /// flachen Liste - Grundlage für die zeilenweise Höhensteuerung in der View (Aufsicht-Zeilen
@@ -99,22 +105,33 @@ public partial class TimetableViewModel : ObservableObject
     public Func<TimetableCellItem, Task>? OnEditSlot { get; set; }
     public Action<Guid>? OnNavigateToGroup { get; set; }
     public Func<Task>? OnAddSubstitution { get; set; }
+    public Func<Task>? OnImportWebUntisTimetable { get; set; }
     public Action<SettingsTab>? OnNavigateToSettings { get; set; }
     public Func<Lesson, Task>? OnOpenLessonViewer { get; set; }
     public Func<Lesson, Task>? OnOpenTeachingMode { get; set; }
+    public Func<TimetableLessonRequest, Task>? OnCreateLesson { get; set; }
+    public Func<TimetableLessonMoveRequest, Task>? OnMoveLesson { get; set; }
+
+    /// Öffentlich statt intern (kein InternalsVisibleTo in dieser Codebasis) - erlaubt Tests, die
+    /// "heute"-abhängiges Verhalten (Wochenraster-Badges, Unterrichtszeit-Erkennung) prüfen, ohne
+    /// vom tatsächlichen Wochentag/der Uhrzeit im Testlauf abzuhängen.
+    public Func<DateTime> Clock { get; set; } = () => DateTime.Now;
 
     public TimetableViewModel(ITimetableSlotRepository slots, IGroupRepository groups,
         ISubjectRepository subjects, ILessonRepository lessons, IExamRepository exams,
         ISchoolHolidayRepository schoolHolidays, SchoolCalendarSettingsService calendarSettings,
         PublicHolidayService publicHolidays, SchoolYearService schoolYear,
         ISupervisionDutyRepository supervisionDuties, ISubstitutionEntryRepository substitutions,
-        IUntisSlotMappingRepository untisMappings, WebUntisSettingsService untisSettings)
+        IUntisSlotMappingRepository untisMappings, WebUntisSettingsService untisSettings,
+        PeriodScheduleService periodSchedule, SchoolWeatherService? schoolWeather = null)
     {
         _slots = slots; _groups = groups; _subjects = subjects; _lessons = lessons; _exams = exams;
         _schoolHolidays = schoolHolidays; _calendarSettings = calendarSettings;
         _publicHolidays = publicHolidays; _schoolYear = schoolYear;
         _supervisionDuties = supervisionDuties; _substitutions = substitutions;
         _untisMappings = untisMappings; _untisSettings = untisSettings;
+        _periodSchedule = periodSchedule;
+        _schoolWeather = schoolWeather;
         Load();
     }
 
@@ -137,9 +154,17 @@ public partial class TimetableViewModel : ObservableObject
         Load();
     }
 
+    [RelayCommand]
+    private async Task ImportWebUntisTimetable()
+    {
+        if (OnImportWebUntisTimetable is null) return;
+        await OnImportWebUntisTimetable();
+        Load();
+    }
+
     public void Load()
     {
-        var today = DateOnly.FromDateTime(DateTime.Today);
+        var today = DateOnly.FromDateTime(Clock());
         TodayLabel = today.ToString("dddd, dd.MM.yyyy", System.Globalization.CultureInfo.GetCultureInfo("de-DE"));
 
         var publicHolidayDates = new HashSet<DateOnly>();
@@ -152,12 +177,58 @@ public partial class TimetableViewModel : ObservableObject
 
         BuildGrid(holidayBadges, duties);
         BuildWeekOverview(today, publicHolidayDates, duties);
+        ApplyWeatherToWeekHeaders(today);
+        _ = LoadWeatherAsync(today);
         BuildToday(today);
         BuildHoursWarnings();
         BuildUpcomingExams(today);
         LoadUntisMismatch();
     }
 
+    private async Task LoadWeatherAsync(DateOnly today)
+    {
+        if (_schoolWeather?.IsAvailable != true) return;
+        if (_weatherSnapshot is not null &&
+            DateTime.UtcNow - _weatherSnapshot.RetrievedAt.ToUniversalTime() < TimeSpan.FromMinutes(5))
+            return;
+        if (!await _weatherGate.WaitAsync(0)) return;
+        try
+        {
+            _weatherSnapshot = await _schoolWeather.GetWeatherAsync();
+            ApplyWeatherToWeekHeaders(today);
+        }
+        catch (SchoolWeatherException) { /* Wetter ist eine optionale Planungshilfe. */ }
+        finally { _weatherGate.Release(); }
+    }
+
+    private void ApplyWeatherToWeekHeaders(DateOnly today)
+    {
+        WeekWeatherWarnings.Clear();
+        var datedHeaders = WeekItems.Where(x => x.IsHeader && x.Date.HasValue).ToList();
+        foreach (var header in datedHeaders)
+        {
+            var date = header.Date!.Value;
+            var warnings = _weatherSnapshot?.Warnings
+                .Where(x => date >= today && SchoolDayWeatherSummary.WarningTouchesDate(x, date))
+                .ToList() ?? [];
+            var summary = date >= today && _weatherSnapshot is not null
+                ? SchoolDayWeatherSummary.From(_weatherSnapshot, date)
+                : null;
+            header.SetWeather(summary, warnings);
+        }
+
+        if (_weatherSnapshot is null || datedHeaders.Count == 0) return;
+        var from = datedHeaders.Min(x => x.Date!.Value);
+        var until = datedHeaders.Max(x => x.Date!.Value);
+        foreach (var warning in _weatherSnapshot.Warnings
+                     .Where(x => Enumerable.Range(0, until.DayNumber - from.DayNumber + 1)
+                         .Select(from.AddDays)
+                         .Any(date => date >= today && SchoolDayWeatherSummary.WarningTouchesDate(x, date)))
+                     .DistinctBy(x => x.Identifier)
+                     .OrderBy(x => x.Onset))
+            WeekWeatherWarnings.Add(new WeekWeatherWarningItem(warning));
+    }
+
     private void LoadUntisMismatch()
     {
         if (!_untisSettings.Enabled || !_untisSettings.IsConfigured) { HasUntisMismatch = false; return; }
@@ -233,9 +304,9 @@ public partial class TimetableViewModel : ObservableObject
             var cancelled = substitutionsToday.FirstOrDefault(s => s.Kind == SubstitutionKind.Cancelled && s.PeriodNumber == slot.PeriodNumber);
             if (cancelled is not null) { items.Add(TodayLessonItem.ForCancelled(slot.GroupId, slot.PeriodNumber, group.Name, cancelled)); continue; }
 
-            var lesson = _lessons.GetByGroupAndDate(slot.GroupId, today).FirstOrDefault();
+            var lesson = FindLessonForSlot(slot.GroupId, today, slot.PeriodNumber);
             var exam = _exams.GetByGroup(slot.GroupId).FirstOrDefault(e => e.Date == today);
-            items.Add(new TodayLessonItem(slot.GroupId, slot.PeriodNumber, group.Name,
+            items.Add(new TodayLessonItem(slot.GroupId, today, slot.PeriodNumber, group.Name,
                 slot.Room ?? "", ColorFor(group.Name), lesson?.Topic, exam?.Title,
                 HasUnhandledHomework(slot.GroupId, today), lesson));
         }
@@ -285,15 +356,15 @@ public partial class TimetableViewModel : ObservableObject
     }
 
     /// Springt aus dem Stundenplan direkt in den Verlaufsplan-Viewer der zugehörigen Lesson (4.5.2)
-    /// — sofern für den Slot schon eine Lesson existiert. Ohne Lesson (Slot laut Stundenplan belegt,
+    /// — sofern für den Slot schon eine Lesson existiert. Ohne Lesson startet die Direktanlage;
-    /// aber noch keine konkrete Stunde geplant) bleibt es bei der bisherigen, gröberen Navigation
+    /// der vorgeschaltete Einheiten-Dialog löst dabei die notwendige Unit-Zuordnung explizit.
-    /// zum Planung-Tab der Gruppe: eine neue Lesson direkt von hier aus anzulegen bräuchte eine
-    /// Antwort auf "welcher Unit wird sie zugeordnet", die bewusst noch offen ist (siehe TODO 4.5.2).
     [RelayCommand]
     private async Task OpenTodayLesson(TodayLessonItem? item)
     {
         if (item is null || item.GroupId == Guid.Empty) return;
         if (item.Lesson is { } lesson && OnOpenLessonViewer is not null) await OnOpenLessonViewer(lesson);
+        else if (OnCreateLesson is not null)
+            await OnCreateLesson(new TimetableLessonRequest(item.GroupId, item.Date, item.PeriodNumber));
         else OnNavigateToGroup?.Invoke(item.GroupId);
     }
 
@@ -307,14 +378,48 @@ public partial class TimetableViewModel : ObservableObject
         await OnOpenTeachingMode(lesson);
     }
 
+    /// Nutzer-Feedback (zweite Runde): der Direktklick auf eine Wochenraster-Kachel soll
+    /// "einheitlicher" springen. Existiert eine Lesson UND ist gerade (heute, mit Toleranz vor/
+    /// nach der Stunde) Unterrichtszeit, geht es direkt in den Unterrichtsmodus — sonst wie
+    /// bisher in den (schreibgeschützten) Planungsviewer bzw., ohne Lesson, zur Einheitenplanung
+    /// der Gruppe. Das Popup-Menü (siehe TimetableView.axaml, MenuFlyout je Kachel) bietet
+    /// daneben die weiteren Ziele (einschließlich Anlegen/Verschieben) explizit an.
     [RelayCommand]
     private async Task OpenWeekCell(WeekCellItem? item)
     {
         if (item is null || item.GroupId == Guid.Empty) return;
-        if (item.Lesson is { } lesson && OnOpenLessonViewer is not null) await OnOpenLessonViewer(lesson);
+        if (item.Lesson is { } lesson)
+        {
+            if (IsAroundTeachingTime(lesson.Date, item.PeriodNumber) && OnOpenTeachingMode is not null)
+                await OnOpenTeachingMode(lesson);
+            else if (OnOpenLessonViewer is not null) await OnOpenLessonViewer(lesson);
+        }
+        else if (item.Date is { } date && OnCreateLesson is not null)
+            await OnCreateLesson(new TimetableLessonRequest(item.GroupId, date, item.PeriodNumber));
         else OnNavigateToGroup?.Invoke(item.GroupId);
     }
 
+    /// Bewusst mit Toleranz vor/nach der eingetragenen Stundenzeit (siehe
+    /// <see cref="PeriodScheduleService"/>, "Stundenraster" in den Einstellungen) statt exakt an
+    /// Start-/Endzeit gebunden — man klickt auch kurz vor Stundenbeginn oder in einer kurzen
+    /// Verzögerung danach noch typischerweise in Unterrichtsabsicht. Ohne konfiguriertes
+    /// Stundenraster oder an einem anderen Tag als heute bleibt es beim Planungsviewer.
+    /// Nimmt das Datum der Lesson selbst entgegen; die Kachel trägt ihr Datum zusätzlich für die
+    /// Direktanlage einer noch nicht existierenden Stunde.
+    private static readonly TimeSpan TeachingTimeTolerance = TimeSpan.FromMinutes(10);
+    private bool IsAroundTeachingTime(DateOnly lessonDate, int periodNumber)
+    {
+        var nowSnapshot = Clock();
+        if (lessonDate != DateOnly.FromDateTime(nowSnapshot)) return false;
+        if (_periodSchedule.GetTimes(periodNumber) is not { } times) return false;
+        // DateTime statt TimeOnly.Add: Letzteres springt nahe Mitternacht auf den anderen
+        // Tagesrand und macht aus z.B. 00:05 ± 10 Minuten ein umgekehrtes Vergleichsfenster.
+        var start = lessonDate.ToDateTime(times.Start).Subtract(TeachingTimeTolerance);
+        var end = lessonDate.ToDateTime(times.End).Add(TeachingTimeTolerance);
+        if (end < start) end = end.AddDays(1); // nur für ein ggf. über Mitternacht laufendes Raster
+        return nowSnapshot >= start && nowSnapshot <= end;
+    }
+
     [RelayCommand]
     private void OpenSettings() => OnNavigateToSettings?.Invoke(SettingsTab.Holidays);
 
@@ -391,14 +496,14 @@ public partial class TimetableViewModel : ObservableObject
                     continue;
                 }
 
-                var lesson = _lessons.GetByGroupAndDate(slot.GroupId, date).FirstOrDefault();
+                var lesson = FindLessonForSlot(slot.GroupId, date, period);
                 var hasExam = _exams.GetByGroup(slot.GroupId).Any(e => e.Date == date);
                 var isHoliday = IsFreeDay(date, schoolHolidays, publicHolidayDates);
                 var colorHex = isHoliday ? "#BDBDBD" : ColorFor(group?.Name ?? "");
                 var holidayBadge = HolidayBadgeFor(date, weekday, schoolHolidays, publicHolidayDates);
                 var isLastBeforeExam = IsLastBeforeExamFor(date, weekday, slot.GroupId, publicHolidayDates);
 
-                WeekItems.Add(WeekCellItem.ForSlot(weekday, period, date == today,
+                WeekItems.Add(WeekCellItem.ForSlot(weekday, period, date == today, date,
                     subject?.ShortName is { Length: > 0 } sn ? sn : subject?.Name ?? "",
                     group?.Name ?? "?", slot.Room ?? "", lesson?.Topic ?? "",
                     colorHex, holidayBadge, hasExam, isLastBeforeExam,
@@ -464,6 +569,40 @@ public partial class TimetableViewModel : ObservableObject
              p.Activity?.Contains("Experiment", StringComparison.OrdinalIgnoreCase) == true ||
              p.Material?.Contains("Experiment", StringComparison.OrdinalIgnoreCase) == true)) == true;
 
+    /// Eine Doppelstunde wird als eine Lesson an der ersten Periode gespeichert. Für die zweite
+    /// Rasterzelle liefern wir dieselbe Lesson, wenn der Stundenplan dort unmittelbar mit derselben
+    /// Lerngruppe fortgesetzt wird. Das darf nicht von bereits eingetragenen Phasendauern abhängen:
+    /// Gerade ein früher Entwurf hat oft erst Datum und Thema, gehört aber trotzdem zum kompletten
+    /// Doppelstundenblock. Eine exakt an der Zielperiode verankerte Lesson hat immer Vorrang.
+    private Lesson? FindLessonForSlot(Guid groupId, DateOnly date, int period)
+    {
+        var lessons = _lessons.GetByGroupAndDate(groupId, date);
+        var exact = lessons.FirstOrDefault(l => l.LessonNumber == period);
+        if (exact is not null) return exact;
+        // Historische/manuell angelegte Einträge hatten häufig keine Stundennummer. Solange es
+        // davon nur einen an diesem Tag gibt, bleibt das frühere Verhalten erhalten und er wird
+        // dem vorhandenen Gruppen-Slot zugeordnet.
+        var withoutPeriod = lessons.Where(l => l.LessonNumber is null).ToList();
+        if (withoutPeriod.Count == 1) return withoutPeriod[0];
+
+        var periodsInBlock = _slots.GetByGroup(groupId)
+            .Where(s => s.Weekday == date.DayOfWeek)
+            .Select(s => s.PeriodNumber)
+            .ToHashSet();
+
+        // Vom angefragten Slot innerhalb desselben lückenlosen Blocks rückwärts zur verankerten
+        // Lesson laufen. Damit funktionieren neben Doppelstunden auch seltene Dreifachblöcke.
+        for (var candidatePeriod = period - 1;
+             periodsInBlock.Contains(candidatePeriod) && periodsInBlock.Contains(candidatePeriod + 1);
+             candidatePeriod--)
+        {
+            var blockLesson = lessons.Where(l => l.LessonNumber == candidatePeriod)
+                .OrderByDescending(l => l.UpdatedAt).FirstOrDefault();
+            if (blockLesson is not null) return blockLesson;
+        }
+        return null;
+    }
+
     /// <summary>4.5.4: Hat die letzte vor <paramref name="date"/> liegende Lesson dieser Gruppe eine
     /// Hausaufgabe, die weder als kontrolliert noch als bewusst übersprungen markiert ist? Schaut
     /// bewusst nur auf die unmittelbar vorherige Lesson (nicht auf die gesamte Historie) — sobald
@@ -689,7 +828,7 @@ public class TimetableRowItem(IReadOnlyList<TimetableCellItem> cells)
 }
 
 /// <summary>Zelle im schreibgeschützten Wochenraster der "Heute"-Ansicht.</summary>
-public class WeekCellItem
+public partial class WeekCellItem : ObservableObject
 {
     public bool IsHeader { get; private init; }
     public bool IsPeriodLabel { get; private init; }
@@ -705,6 +844,7 @@ public class WeekCellItem
     public DayOfWeek? Weekday { get; private init; }
     public int PeriodNumber { get; private init; }
     public bool IsToday { get; private init; }
+    public DateOnly? Date { get; private init; }
     public Guid GroupId { get; private init; }
     public string SubjectLabel { get; private init; } = "";
     public string GroupName { get; private init; } = "";
@@ -722,10 +862,36 @@ public class WeekCellItem
     public bool HasSupervision => SupervisionLocation.Length > 0;
     public bool HasRoom => !string.IsNullOrWhiteSpace(Room);
     public bool HasTopic => !string.IsNullOrWhiteSpace(Topic);
+    public bool HasGroupId => GroupId != Guid.Empty;
     /// Nur bei einer regulären, zugewiesenen Zelle mit bereits existierender Lesson gesetzt —
     /// Grundlage für den Direktsprung in den Verlaufsplan-Viewer (4.5.2).
     public Lesson? Lesson { get; private init; }
-    public string OpenButtonLabel => Lesson is not null ? "Verlaufsplan ansehen" : "Zur Lerngruppe";
+    public bool HasLesson => Lesson is not null;
+    public bool HasNoLesson => Lesson is null;
+    public string PlanningStatusLabel => Lesson is null ? "Nicht geplant" : LessonStatusDisplay.ToName(Lesson.Status);
+    public string OpenButtonLabel => Lesson is not null ? "Verlaufsplan ansehen" : "Stunde anlegen";
+    [ObservableProperty] private string _weatherSymbol = "";
+    [ObservableProperty] private string _weatherTooltip = "";
+    [ObservableProperty] private bool _hasWeatherWarning;
+    public bool HasWeather => WeatherSymbol.Length > 0;
+    public bool HasWeatherInformation => HasWeather || HasWeatherWarning;
+
+    partial void OnWeatherSymbolChanged(string value)
+    {
+        OnPropertyChanged(nameof(HasWeather));
+        OnPropertyChanged(nameof(HasWeatherInformation));
+    }
+
+    partial void OnHasWeatherWarningChanged(bool value) =>
+        OnPropertyChanged(nameof(HasWeatherInformation));
+
+    public void SetWeather(SchoolDayWeatherSummary? summary, IReadOnlyList<WeatherWarning> warnings)
+    {
+        WeatherSymbol = summary?.Symbol ?? "";
+        WeatherTooltip = summary?.Tooltip ?? string.Join("\n", warnings.Select(x =>
+            $"⚠ {x.Headline} ({SchoolDayWeatherSummary.WarningPeriod(x)})"));
+        HasWeatherWarning = warnings.Count > 0;
+    }
 
     public static WeekCellItem Corner() => new() { IsHeader = true };
 
@@ -733,6 +899,7 @@ public class WeekCellItem
     {
         IsHeader = true,
         IsToday = isToday,
+        Date = date,
         Text = (day switch
         {
             DayOfWeek.Monday => "Mo", DayOfWeek.Tuesday => "Di", DayOfWeek.Wednesday => "Mi",
@@ -757,18 +924,28 @@ public class WeekCellItem
         IsSubstitutionSupervision = isSubstitution,
     };
 
-    public static WeekCellItem ForSlot(DayOfWeek day, int period, bool isToday, string subjectLabel,
+    public static WeekCellItem ForSlot(DayOfWeek day, int period, bool isToday, DateOnly date, string subjectLabel,
         string groupName, string room, string topic, string colorHex, string holidayBadge,
         bool hasExam, bool isLastBeforeExam, bool hasExperiment, Guid groupId, bool isHoliday,
         bool hasUnhandledHomework = false, Lesson? lesson = null) => new()
     {
-        Weekday = day, PeriodNumber = period, IsAssigned = true, IsToday = isToday,
+        Weekday = day, PeriodNumber = period, IsAssigned = true, IsToday = isToday, Date = date,
         SubjectLabel = subjectLabel, GroupName = groupName, Room = room, Topic = topic,
         ColorHex = colorHex, HolidayBadge = holidayBadge, HasExam = hasExam,
         IsLastBeforeExam = isLastBeforeExam, HasExperiment = hasExperiment, GroupId = groupId,
         IsHoliday = isHoliday, HasUnhandledHomework = hasUnhandledHomework, Lesson = lesson,
     };
 
+    // Kompatible Überladung für isolierte ViewModel-Tests und ältere Aufrufer ohne konkreten
+    // Wochenbezug. Produktiv wird die datierte Variante verwendet.
+    public static WeekCellItem ForSlot(DayOfWeek day, int period, bool isToday, string subjectLabel,
+        string groupName, string room, string topic, string colorHex, string holidayBadge,
+        bool hasExam, bool isLastBeforeExam, bool hasExperiment, Guid groupId, bool isHoliday,
+        bool hasUnhandledHomework = false, Lesson? lesson = null) => ForSlot(day, period, isToday,
+            DateOnly.FromDateTime(DateTime.Today), subjectLabel, groupName, room, topic, colorHex,
+            holidayBadge, hasExam, isLastBeforeExam, hasExperiment, groupId, isHoliday,
+            hasUnhandledHomework, lesson);
+
     public static WeekCellItem ForSubstitutionLesson(DayOfWeek day, int period, bool isToday, SubstitutionEntry entry) => new()
     {
         Weekday = day, PeriodNumber = period, IsAssigned = true, IsToday = isToday, IsSubstitutionLesson = true,
@@ -815,9 +992,13 @@ public class UpcomingExamItem(DateOnly date, string groupName, string title)
     public string Title { get; } = title;
 }
 
+public enum TimetableLessonDestination { TeachingMode, Viewer, Create, Move, SeatingPlan, Planning }
+public sealed record TimetableDestinationOption(TimetableLessonDestination Kind, string Label);
+
 public class TodayLessonItem
 {
     public Guid GroupId { get; private init; }
+    public DateOnly Date { get; private init; }
     public int PeriodNumber { get; private init; }
     public string GroupName { get; private init; } = "";
     public string Room { get; private init; } = "";
@@ -835,23 +1016,24 @@ public class TodayLessonItem
     /// Direktsprung in den Verlaufsplan-Viewer (4.5.2) und den Unterrichtsmodus (14.x).
     public Lesson? Lesson { get; private init; }
     public bool HasLesson => Lesson is not null;
-    public string OpenButtonLabel => Lesson is not null ? "Verlaufsplan ansehen" : "Zur Lerngruppe";
+    public string PlanningStatusLabel => Lesson is null ? "Nicht geplant" : LessonStatusDisplay.ToName(Lesson.Status);
+    public string OpenButtonLabel => Lesson is not null ? "Verlaufsplan ansehen" : "Stunde anlegen";
 
-    public TodayLessonItem(Guid groupId, int periodNumber, string groupName, string room,
+    public TodayLessonItem(Guid groupId, DateOnly date, int periodNumber, string groupName, string room,
         string colorHex, string? lessonTopic, string? examTitle, bool hasUnhandledHomework = false,
         Lesson? lesson = null)
     {
-        GroupId = groupId; PeriodNumber = periodNumber; GroupName = groupName; Room = room;
+        GroupId = groupId; Date = date; PeriodNumber = periodNumber; GroupName = groupName; Room = room;
         ColorHex = colorHex; LessonTopic = lessonTopic; ExamTitle = examTitle;
         HasUnhandledHomework = hasUnhandledHomework; Lesson = lesson;
     }
 
     public static TodayLessonItem ForSubstitution(int periodNumber, SubstitutionEntry entry) => new(
-        entry.GroupId ?? Guid.Empty, periodNumber, entry.GroupLabel, "", "#8E24AA", entry.Description, null)
+        entry.GroupId ?? Guid.Empty, entry.Date, periodNumber, entry.GroupLabel, "", "#8E24AA", entry.Description, null)
     { IsSubstitution = true };
 
     public static TodayLessonItem ForCancelled(Guid groupId, int periodNumber, string groupName, SubstitutionEntry entry) => new(
-        groupId, periodNumber, groupName, "", "#757575",
+        groupId, entry.Date, periodNumber, groupName, "", "#757575",
         string.IsNullOrWhiteSpace(entry.Description) ? null : entry.Description, null)
     { IsCancelled = true };
 }

LehrerApp.Desktop/ViewModels/Planning/WebUntisTimetableImportViewModel.cs

@@ -0,0 +1,159 @@
+using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Desktop.Services;
+
+namespace LehrerApp.Desktop.ViewModels.Planning;
+
+public sealed record WebUntisGroupOption(Guid Id, string DisplayName);
+
+public partial class WebUntisTimetableRow : ObservableObject
+{
+    public required DayOfWeek Weekday { get; init; }
+    public required int PeriodNumber { get; init; }
+    public required string TimeLabel { get; init; }
+    public required string UntisLabel { get; init; }
+    public required string SuggestedGroupName { get; init; }
+    public string? SubjectName { get; init; }
+    public string? Room { get; init; }
+    public ObservableCollection<WebUntisGroupOption> GroupOptions { get; } = [];
+    [ObservableProperty] private WebUntisGroupOption? _selectedGroup;
+    public string WeekdayLabel => Weekday switch
+    {
+        DayOfWeek.Monday => "Mo", DayOfWeek.Tuesday => "Di", DayOfWeek.Wednesday => "Mi",
+        DayOfWeek.Thursday => "Do", DayOfWeek.Friday => "Fr", _ => Weekday.ToString()[..2],
+    };
+}
+
+public partial class WebUntisTimetableImportViewModel : ObservableObject
+{
+    private readonly WebUntisIntegrationService _untis;
+    private readonly WebUntisSettingsService _settings;
+    private readonly ITimetableSlotRepository _slots;
+    private readonly IGroupRepository _groups;
+
+    public ObservableCollection<UntisTeacherDto> Teachers { get; } = [];
+    public ObservableCollection<WebUntisTimetableRow> Rows { get; } = [];
+    [ObservableProperty] private UntisTeacherDto? _selectedTeacher;
+    [ObservableProperty] private DateTimeOffset _weekDate = DateTimeOffset.Now;
+    [ObservableProperty] private string _status = "Lehrkraft auswählen und Untis-Woche laden.";
+    [ObservableProperty] private bool _busy;
+    public bool Saved { get; private set; }
+    public Func<WebUntisTimetableRow, Task<LearningGroup?>>? OnCreateGroup { get; set; }
+
+    public WebUntisTimetableImportViewModel(WebUntisIntegrationService untis, WebUntisSettingsService settings,
+        ITimetableSlotRepository slots, IGroupRepository groups)
+    {
+        _untis = untis; _settings = settings; _slots = slots; _groups = groups;
+    }
+
+    public async Task InitializeAsync()
+    {
+        Busy = true;
+        try
+        {
+            foreach (var teacher in (await _untis.GetTeachersAsync()).Where(x => x.Active).OrderBy(x => x.DisplayName))
+                Teachers.Add(teacher);
+            SelectedTeacher = Teachers.FirstOrDefault(x => x.UntisId == _settings.TeacherUntisId)
+                              ?? Teachers.FirstOrDefault();
+            Status = Teachers.Count == 0 ? "WebUntis hat keine Lehrkräfte geliefert." : "Bereit zum Laden.";
+        }
+        catch (WebUntisIntegrationException ex) { Status = ex.Message; }
+        finally { Busy = false; }
+    }
+
+    [RelayCommand]
+    private async Task Load()
+    {
+        if (SelectedTeacher is null) { Status = "Bitte eine Lehrkraft auswählen."; return; }
+        Busy = true; Rows.Clear();
+        try
+        {
+            var selected = DateOnly.FromDateTime(WeekDate.LocalDateTime);
+            var monday = selected.AddDays(-(((int)selected.DayOfWeek + 6) % 7));
+            var periods = await _untis.GetTimetableAsync(SelectedTeacher.UntisId, monday, monday.AddDays(6));
+            var grid = await _untis.GetTimeGridAsync();
+            var groupOptions = BuildGroupOptions();
+            var localSlots = _slots.GetAll().ToDictionary(x => (x.Weekday, x.PeriodNumber));
+
+            foreach (var period in periods.Where(x => string.IsNullOrWhiteSpace(x.Code) || x.Code != "cancelled")
+                         .GroupBy(x => (x.Date, x.StartTime, x.EndTime, x.StudentGroup,
+                             Class: string.Join("/", x.Classes.Select(c => c.Name)),
+                             Subject: string.Join("/", x.Subjects.Select(s => s.Name)),
+                             Room: string.Join("/", x.Rooms.Select(r => r.Name))))
+                         .Select(x => x.First()).OrderBy(x => x.Date).ThenBy(x => x.StartTime))
+            {
+                if (!TryDate(period.Date, out var date) || date.DayOfWeek is DayOfWeek.Saturday or DayOfWeek.Sunday)
+                    continue;
+                var dayGrid = grid.FirstOrDefault(x => x.Day == UntisDay(date.DayOfWeek));
+                var number = dayGrid?.TimeUnits.ToList().FindIndex(x => x.StartTime == period.StartTime) + 1 ?? 0;
+                if (number <= 0) continue;
+                var className = period.Classes.FirstOrDefault()?.Name ?? "";
+                var subject = period.Subjects.FirstOrDefault()?.Name;
+                var suggested = !string.IsNullOrWhiteSpace(period.StudentGroup) ? period.StudentGroup! : className;
+                var row = new WebUntisTimetableRow
+                {
+                    Weekday = date.DayOfWeek, PeriodNumber = number,
+                    TimeLabel = $"{Time(period.StartTime)}–{Time(period.EndTime)}",
+                    UntisLabel = string.Join(" · ", new[] { subject, suggested, period.Rooms.FirstOrDefault()?.Name }
+                        .Where(x => !string.IsNullOrWhiteSpace(x))),
+                    SuggestedGroupName = suggested, SubjectName = subject,
+                    Room = period.Rooms.FirstOrDefault()?.Name,
+                };
+                foreach (var option in groupOptions) row.GroupOptions.Add(option);
+                if (localSlots.TryGetValue((row.Weekday, row.PeriodNumber), out var existing))
+                    row.SelectedGroup = groupOptions.FirstOrDefault(x => x.Id == existing.GroupId);
+                row.SelectedGroup ??= BestMatch(groupOptions, suggested, className, subject);
+                Rows.Add(row);
+            }
+            _settings.SetTeacherUntisId(SelectedTeacher.UntisId);
+            Status = Rows.Count == 0 ? "In dieser Woche wurde kein Unterricht gefunden."
+                : $"{Rows.Count} regelmäßige Termine gefunden. Zuordnung prüfen und übernehmen.";
+        }
+        catch (WebUntisIntegrationException ex) { Status = ex.Message; }
+        finally { Busy = false; }
+    }
+
+    [RelayCommand]
+    private async Task CreateGroup(WebUntisTimetableRow row)
+    {
+        if (OnCreateGroup is null) return;
+        var group = await OnCreateGroup(row);
+        if (group is null) return;
+        var option = new WebUntisGroupOption(group.Id, group.Name);
+        foreach (var item in Rows.Where(x => x.SuggestedGroupName == row.SuggestedGroupName))
+        {
+            item.GroupOptions.Add(option);
+            item.SelectedGroup = option;
+        }
+    }
+
+    [RelayCommand]
+    private void Save()
+    {
+        var selected = Rows.Where(x => x.SelectedGroup is not null).ToList();
+        foreach (var row in selected)
+        {
+            var existing = _slots.GetAll().FirstOrDefault(x => x.Weekday == row.Weekday && x.PeriodNumber == row.PeriodNumber);
+            var slot = existing ?? new TimetableSlot { Weekday = row.Weekday, PeriodNumber = row.PeriodNumber };
+            slot.GroupId = row.SelectedGroup!.Id;
+            slot.Room = string.IsNullOrWhiteSpace(row.Room) ? null : row.Room;
+            _slots.Save(slot);
+        }
+        Saved = true;
+        Status = $"{selected.Count} Stundenplan-Einträge übernommen.";
+    }
+
+    private List<WebUntisGroupOption> BuildGroupOptions() => _groups.GetAll().OrderBy(x => x.Name)
+        .Select(x => new WebUntisGroupOption(x.Id, x.Name)).ToList();
+
+    private static WebUntisGroupOption? BestMatch(IEnumerable<WebUntisGroupOption> options, params string?[] terms) =>
+        options.FirstOrDefault(x => terms.Any(term => !string.IsNullOrWhiteSpace(term) &&
+            (x.DisplayName.Equals(term, StringComparison.OrdinalIgnoreCase) ||
+             x.DisplayName.Contains(term, StringComparison.OrdinalIgnoreCase))));
+    private static int UntisDay(DayOfWeek day) => day == DayOfWeek.Sunday ? 7 : (int)day;
+    private static bool TryDate(int value, out DateOnly date) => DateOnly.TryParseExact(value.ToString(), "yyyyMMdd", out date);
+    private static string Time(int value) => $"{value / 100:00}:{value % 100:00}";
+}

LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.AiSettings.cs

@@ -0,0 +1,81 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Data;
+using LehrerApp.Desktop.Services;
+using LehrerApp.Desktop.ViewModels.Planning;
+using LehrerApp.Sync;
+using LehrerApp.Sync.Crypto;
+using System.Collections.ObjectModel;
+using System.Globalization;
+using System.Security.Cryptography;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace LehrerApp.Desktop.ViewModels.Settings;
+
+public partial class SettingsViewModel
+{
+    // ── KI-Unterstützung (4.5.9) ──────────────────────────────────────────────
+
+    [ObservableProperty] private bool   _aiEnabled;
+    [ObservableProperty] private string _aiUsername = "";
+    [ObservableProperty] private string _aiPassword = "";
+    [ObservableProperty] private string _aiLoginError = "";
+    [ObservableProperty] private bool   _aiIsLoggedIn;
+    [ObservableProperty] private string _aiBalanceDisplay = "";
+
+    // ── KI-Unterstützung: Laden / Anmelden / Abmelden ────────────────────────
+
+    private void LoadAiSettings()
+    {
+        AiEnabled = _aiSettings.Enabled;
+        AiUsername = _aiSettings.Username;
+        AiIsLoggedIn = _aiSettings.IsLoggedIn;
+        if (AiIsLoggedIn) _ = RefreshAiBalance();
+    }
+
+    partial void OnAiEnabledChanged(bool value) => _aiSettings.SetEnabled(value);
+
+    private async Task RefreshAiBalance()
+    {
+        var token = _aiSettings.GetToken();
+        if (token is null) return;
+        try
+        {
+            var balance = await _aiPlanning.GetBalanceAsync(token);
+            AiBalanceDisplay = $"Guthaben: {balance:0.00} €";
+        }
+        catch (AiBackendException ex) { AiBalanceDisplay = ex.Message; }
+    }
+
+    [RelayCommand]
+    private async Task AiLogin()
+    {
+        AiLoginError = "";
+        var valid = true;
+        if (string.IsNullOrWhiteSpace(AiUsername)) { AiLoginError = "Benutzername erforderlich."; valid = false; }
+        if (string.IsNullOrWhiteSpace(AiPassword)) { AiLoginError = "Passwort erforderlich."; valid = false; }
+        if (!valid) return;
+
+        try
+        {
+            var token = await _aiPlanning.LoginAsync(AiUsername, AiPassword);
+            _aiSettings.SetCredentialsAndToken(AiUsername, token);
+            AiPassword = "";
+            AiIsLoggedIn = true;
+            await RefreshAiBalance();
+        }
+        catch (AiBackendException ex) { AiLoginError = ex.Message; }
+    }
+
+    [RelayCommand]
+    private void AiLogout()
+    {
+        _aiSettings.Logout();
+        AiIsLoggedIn = false;
+        AiBalanceDisplay = "";
+    }
+}

LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.AnnualPlan.cs

@@ -0,0 +1,90 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Data;
+using LehrerApp.Desktop.Services;
+using LehrerApp.Desktop.ViewModels.Planning;
+using LehrerApp.Sync;
+using LehrerApp.Sync.Crypto;
+using System.Collections.ObjectModel;
+using System.Globalization;
+using System.Security.Cryptography;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace LehrerApp.Desktop.ViewModels.Settings;
+
+public partial class SettingsViewModel
+{
+    // ── Schulweiter Jahresplan (ClassyPlan-iCal) ─────────────────────────────
+
+    [ObservableProperty] private bool _annualPlanIsConfigured;
+    [ObservableProperty] private string _annualPlanIcalUrlInput = "";
+    [ObservableProperty] private string _annualPlanUrlError = "";
+    [ObservableProperty] private string _annualPlanStatusDisplay = "";
+    [ObservableProperty] private bool _annualPlanFetchBusy;
+
+    // ── Schulweiter Jahresplan: Laden / Speichern / Entfernen / Jetzt abrufen ─
+
+    private void LoadAnnualPlanSettings()
+    {
+        AnnualPlanIsConfigured = _annualPlanSettings.IsConfigured;
+        AnnualPlanStatusDisplay = _annualPlanSettings.LastSyncAt is { } at
+            ? $"Letzter Abgleich: {at.ToLocalTime():dd.MM.yyyy HH:mm} — {_annualPlanSettings.LastSyncStatus}"
+            : "Noch kein Abgleich durchgeführt.";
+    }
+
+    [RelayCommand]
+    private void AnnualPlanSaveUrl()
+    {
+        AnnualPlanUrlError = "";
+        if (string.IsNullOrWhiteSpace(AnnualPlanIcalUrlInput))
+        {
+            AnnualPlanUrlError = "iCal-URL erforderlich.";
+            return;
+        }
+        if (!Uri.TryCreate(AnnualPlanIcalUrlInput, UriKind.Absolute, out var uri) ||
+            uri.Scheme is not ("http" or "https"))
+        {
+            AnnualPlanUrlError = "Ungültige HTTP(S)-URL.";
+            return;
+        }
+
+        _annualPlanSettings.SetIcalUrl(AnnualPlanIcalUrlInput.Trim());
+        _annualPlanSettings.SetEnabled(true);
+        AnnualPlanIcalUrlInput = "";
+        AppBootstrapper.RestartApplication();
+    }
+
+    [RelayCommand]
+    private void AnnualPlanRemove()
+    {
+        _annualPlanSync?.Clear();
+        _annualPlanSettings.ClearIcalUrl();
+        LoadAnnualPlanSettings();
+        AppBootstrapper.RestartApplication();
+    }
+
+    [RelayCommand]
+    private async Task AnnualPlanFetchNow()
+    {
+        if (_annualPlanSync is null)
+        {
+            AnnualPlanStatusDisplay = "Abgleich nicht aktiv — App neu starten.";
+            return;
+        }
+
+        AnnualPlanFetchBusy = true;
+        try
+        {
+            await _annualPlanSync.PollAsync();
+            LoadAnnualPlanSettings();
+        }
+        finally
+        {
+            AnnualPlanFetchBusy = false;
+        }
+    }
+}

LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.AppLock.cs

@@ -0,0 +1,74 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Data;
+using LehrerApp.Desktop.Services;
+using LehrerApp.Desktop.ViewModels.Planning;
+using LehrerApp.Sync;
+using LehrerApp.Sync.Crypto;
+using System.Collections.ObjectModel;
+using System.Globalization;
+using System.Security.Cryptography;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace LehrerApp.Desktop.ViewModels.Settings;
+
+public partial class SettingsViewModel
+{
+    // ── Sicherheit: App-Sperre nach Inaktivität (13.3.5) ─────────────────────
+
+    [ObservableProperty] private bool   _appLockEnabled;
+    [ObservableProperty] private int    _appLockTimeoutMinutes = 10;
+    [ObservableProperty] private string _appLockNewPassword        = "";
+    [ObservableProperty] private string _appLockNewPasswordConfirm = "";
+    [ObservableProperty] private string _appLockPasswordError      = "";
+    [ObservableProperty] private string _appLockStatus             = "";
+
+    public bool AppLockHasPassword => _appLock.HasPassword;
+
+    /// Vom Code-Behind gesetzt: aktualisiert den laufenden Inaktivitäts-Timer sofort,
+    /// ohne dass die App neu gestartet werden muss.
+    public Action? OnAppLockChanged { get; set; }
+
+    // ── App-Sperre: Speichern ─────────────────────────────────────────────────
+
+    [RelayCommand]
+    private void SaveAppLockSettings()
+    {
+        AppLockPasswordError = "";
+        var valid = true;
+        var wantsNewPassword = !string.IsNullOrWhiteSpace(AppLockNewPassword) || !string.IsNullOrWhiteSpace(AppLockNewPasswordConfirm);
+
+        if (AppLockEnabled && !_appLock.HasPassword && !wantsNewPassword)
+        {
+            AppLockPasswordError = "Bitte ein Passwort für die App-Sperre festlegen.";
+            valid = false;
+        }
+        else if (wantsNewPassword)
+        {
+            if (AppLockNewPassword != AppLockNewPasswordConfirm)
+            {
+                AppLockPasswordError = "Passwörter stimmen nicht überein.";
+                valid = false;
+            }
+            else if (AppLockNewPassword.Length < 4)
+            {
+                AppLockPasswordError = "Mindestens 4 Zeichen.";
+                valid = false;
+            }
+        }
+
+        if (!valid) return;
+
+        if (wantsNewPassword) _appLock.SetPassword(AppLockNewPassword.Trim());
+        _appLock.Configure(AppLockEnabled, AppLockTimeoutMinutes);
+
+        AppLockNewPassword = ""; AppLockNewPasswordConfirm = "";
+        OnPropertyChanged(nameof(AppLockHasPassword));
+        AppLockStatus = "Gespeichert.";
+        OnAppLockChanged?.Invoke();
+    }
+}

LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.Appearance.cs

@@ -0,0 +1,41 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Data;
+using LehrerApp.Desktop.Services;
+using LehrerApp.Desktop.ViewModels.Planning;
+using LehrerApp.Sync;
+using LehrerApp.Sync.Crypto;
+using System.Collections.ObjectModel;
+using System.Globalization;
+using System.Security.Cryptography;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace LehrerApp.Desktop.ViewModels.Settings;
+
+public partial class SettingsViewModel
+{
+    // ── Darstellung (12.4) ──────────────────────────────────────────────────────
+
+    [ObservableProperty] private AppTheme _selectedTheme;
+    public string[] ThemeOptions { get; } = AppThemeDisplay.Options;
+    public string SelectedThemeName
+    {
+        get => AppThemeDisplay.Label(SelectedTheme);
+        set => SelectedTheme = AppThemeDisplay.FromLabel(value);
+    }
+
+    /// Vom Code-Behind gesetzt: wendet die Theme-Variante sofort an (Application.Current, siehe
+    /// App.ApplyTheme) — ViewModels fassen Avalonia-Framework-Typen nicht direkt an, gleiches
+    /// Muster wie die übrigen Code-Behind-Hooks in dieser Klasse.
+    public Action<AppTheme>? OnThemeChanged { get; set; }
+
+    partial void OnSelectedThemeChanged(AppTheme value)
+    {
+        _appearance.Save(value);
+        OnThemeChanged?.Invoke(value);
+    }
+}

LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.Backup.cs

@@ -0,0 +1,92 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Core.Services;
+using LehrerApp.Data;
+using LehrerApp.Desktop.Services;
+using LehrerApp.Desktop.ViewModels.Planning;
+using LehrerApp.Sync;
+using LehrerApp.Sync.Crypto;
+using System.Collections.ObjectModel;
+using System.Globalization;
+using System.Security.Cryptography;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace LehrerApp.Desktop.ViewModels.Settings;
+
+public partial class SettingsViewModel
+{
+    // ── Sicherheit: Datensicherung (13.3.1/13.3.2) ───────────────────────────
+
+    [ObservableProperty] private string _backupStatus = "";
+    [ObservableProperty] private string _secondaryBackupDirectory = "";
+    public ObservableCollection<BackupListItem> Backups { get; } = [];
+
+    /// Vom Code-Behind gesetzt: zeigt einen Bestätigungsdialog vor dem Wiederherstellen.
+    public Func<BackupListItem, Task<bool>>? OnConfirmRestore { get; set; }
+
+    /// Vom Code-Behind gesetzt: öffnet einen Ordnerauswahl-Dialog für das zweite Sicherungsziel.
+    public Func<Task<string?>>? OnPickBackupDirectory { get; set; }
+
+    // ── Datensicherung: Laden / Erstellen / Wiederherstellen ─────────────────
+
+    private void LoadBackups()
+    {
+        Backups.Clear();
+        foreach (var b in _backups.ListBackups()) Backups.Add(new BackupListItem(b));
+        SecondaryBackupDirectory = _backupSettings.LoadSecondaryDirectory() ?? "";
+    }
+
+    [RelayCommand]
+    private void CreateBackupNow()
+    {
+        var path = _backups.CreateBackup(AppBootstrapper.DbPath);
+        LoadBackups();
+        if (path is null) { BackupStatus = "Kein Backup erstellt (Datenbankdatei fehlt)."; return; }
+
+        BackupStatus = _dbEncryption.CanOpenAndRead(path, AppBootstrapper.DbPassword)
+            ? "Backup erstellt und geprüft."
+            : "Backup erstellt — Prüfung fehlgeschlagen, Datei könnte beschädigt sein!";
+    }
+
+    [RelayCommand]
+    private async Task PickBackupDirectory()
+    {
+        if (OnPickBackupDirectory is null) return;
+        var path = await OnPickBackupDirectory();
+        if (path is null) return;
+
+        _backupSettings.SaveSecondaryDirectory(path);
+        _backups.SecondaryBackupDirectory = path;
+        SecondaryBackupDirectory = path;
+        BackupStatus = "Zweiter Sicherungsordner gespeichert.";
+    }
+
+    [RelayCommand]
+    private void ClearBackupDirectory()
+    {
+        _backupSettings.SaveSecondaryDirectory(null);
+        _backups.SecondaryBackupDirectory = null;
+        SecondaryBackupDirectory = "";
+        BackupStatus = "Zweiter Sicherungsordner entfernt.";
+    }
+
+    [RelayCommand]
+    private async Task RestoreBackup(BackupListItem? item)
+    {
+        if (item is null) return;
+        if (OnConfirmRestore is not null && !await OnConfirmRestore(item)) return;
+
+        _dbContext.Dispose();
+        _backups.RestoreBackup(item.Path, AppBootstrapper.DbPath);
+        AppBootstrapper.RestartApplication();
+    }
+}
+
+public class BackupListItem(BackupInfo info)
+{
+    public string Path    { get; } = info.Path;
+    public string Display { get; } = $"{info.CreatedAt:dd.MM.yyyy HH:mm} · {info.SizeBytes / 1024.0:0} KB";
+}