Datepicker update

# Conflicts:
#	LehrerApp.TemplateDesigner.Tests/ProjectLifecycleTests.cs
#	LehrerApp.TemplateDesigner/DesignerViewModel.cs
#	LehrerApp.TemplateDesigner/MainWindow.axaml
#	LehrerApp.Templating/LayoutParser.cs
#	LehrerApp.Templating/QuestTemplateRenderer.cs

.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",

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,
-         die im Server-Image (LehrerApp.Api) nichts verloren haben. -->
+    <!-- PDF-Erzeugung: Desktop-Exporte und die unabhängige Templating-Library. -->
     <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.Core/Interfaces/IRepositories.cs

@@ -225,6 +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/LearningGroup.cs

@@ -26,6 +26,13 @@ public class LearningGroup
     /// 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/Workload.cs

@@ -93,7 +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/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 +60,7 @@ 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.
         };

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/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/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);

LehrerApp.Desktop.Tests/ClassTeacherViewModelsTests.cs

@@ -184,7 +184,8 @@ public sealed class ClassTeacherViewModelsTests
         };
 
         var row = Assert.Single(ClassTeacherRosterRow.Build(students, [], [],
-            new DateOnly(2026, 8, 26), yearAbsences, schoolDaysElapsed: 20));
+            new DateOnly(2026, 8, 26), yearAbsences, schoolDaysElapsed: 20,
+            termStart: new DateOnly(2026, 8, 1)));
 
         Assert.True(row.HasYearSummary);
         Assert.Equal(2, row.YearAbsenceDayCount);
@@ -192,9 +193,29 @@ public sealed class ClassTeacherViewModelsTests
         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()
     {
@@ -264,6 +285,79 @@ public sealed class ClassTeacherViewModelsTests
         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]
@@ -290,6 +384,87 @@ public sealed class ClassTeacherViewModelsTests
         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]

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(student, new LetterTemplateService(_directory));
-
+        var vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), new TemplateStore(_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), service);
-
+        var vm = Build(StudentWithContact(null), StoreWithTemplate(
+            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 vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), service);
-        var output = Path.Combine(_directory, "Brief.docx");
+        var store = StoreWithTemplate(new PlaceholderDefinition("Anrede", PlaceholderType.Text, true),
+            new PlaceholderDefinition("Datum", PlaceholderType.Date, true),
+            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(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);
+        Assert.True(vm.Generate(output));
+        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(output), 0, 4));
     }
 
     [Fact]
-    public void KontaktBearbeiten_SpeichertExpliziteBriefanrede()
+    public void KonstanterPflichttext_BenoetigtKeineExterneEingabe()
     {
-        var vm = new ContactEditDialogViewModel(new Contact { Name = "Frau Muster" });
-        vm.LetterSalutation = "Sehr geehrte Frau Muster,";
+        var store = StoreWithTemplate(new PlaceholderDefinition("Brieftext", PlaceholderType.Multiline,
+            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.Equal("Sehr geehrte Frau Muster,", vm.Result!.LetterSalutation);
+        Assert.True(vm.CanGenerate);
+        Assert.True(vm.Generate(output));
+        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(output), 0, 4));
     }
 
-    private CreateLetterDialogViewModel Build(Student student, LetterTemplateService service) =>
-        new(student, service, new FakeMemberships([]), new FakeGroups([]));
+    private CreateLetterDialogViewModel Build(Student student, TemplateStore store) =>
+        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");
-        using (var archive = ZipFile.Open(source, ZipArchiveMode.Create))
+        var source = Path.Combine(_directory, $"{Guid.NewGuid():N}.lavorlage");
+        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");
-            using var writer = new StreamWriter(entry.Open());
-            var controls = string.Join("", tags.Select(tag =>
-                $"<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 element = definition.Type == PlaceholderType.Multiline ? "TEXTBOX" : "TEXT";
+            lines.Add(element == "TEXTBOX" ? $"TEXTBOX 20 {y} 170 80 ${definition.Name}" : $"TEXT 20 {y} ${definition.Name}");
+            y += 20;
         }
-        var service = new LetterTemplateService(Path.Combine(_directory, $"service-{Guid.NewGuid():N}"));
-        service.Import(source, "Elternbrief");
-        return service;
+        TemplatePackage.Create(source, manifest, string.Join('\n', lines), new Dictionary<string, byte[]>());
+        var store = new TemplateStore(Path.Combine(_directory, $"store-{Guid.NewGuid():N}")); store.Import(source); return store;
     }
 
     private static Student StudentWithContact(string? salutation) => new()
     {
-        FirstName = "Lena",
-        LastName = "Beispiel",
-        Contacts =
-        [
-            new Contact
-            {
-                Name = "Frau Muster",
-                Relation = "Mutter",
-                LetterSalutation = salutation,
-                Street = "Hauptstraße 1",
-                PostalCode = "12345",
-                City = "Musterstadt",
-            },
-        ],
+        FirstName = "Lena", LastName = "Beispiel",
+        Contacts = [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, recursive: true);
-    }
+    public void Dispose() { if (Directory.Exists(_directory)) Directory.Delete(_directory, 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;
@@ -59,12 +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(),
@@ -72,7 +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]
@@ -242,6 +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/ExamsOverviewViewModelTests.cs

@@ -29,6 +29,20 @@ public sealed class ExamsOverviewViewModelTests
         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()
     {

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);

LehrerApp.Desktop.Tests/GlobalSearchViewModelTests.cs

@@ -14,7 +14,8 @@ public sealed class GlobalSearchViewModelTests
         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.NewStudent, item.Action),
+            item => Assert.Equal(GlobalSearchAction.NewGroupDocumentation, item.Action));
         Assert.Same(vm.Results[0], vm.SelectedResult);
     }
 
@@ -67,8 +68,36 @@ public sealed class GlobalSearchViewModelTests
         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<LearningGroup>? groups = null, List<Exam>? exams = null, FakeWorkTasks? tasks = null,
+        List<Subject>? subjects = null) =>
         new(new FakeStudents(students ?? []), new FakeGroups(groups ?? []),
-            new FakeExams(exams ?? []), tasks ?? new FakeWorkTasks());
+            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 FakeDocumentation(), tasks, new AttendanceBalanceService(), new SchoolYearService()),
+            new GroupOverviewViewModel(new FakeLessons(), exams, new FakeResults(), new FakeSessions([]), new FakeEntries(), students,
+                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/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) =>
-        new(lessons ?? new FakeLessons(), exams ?? new FakeExams([]), sessions ?? new FakeSessions([]),
+        FakeDocumentation? documentation = null, FakeWorkTasks? tasks = null,
+        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/PlanningTabViewModelTests.cs

@@ -294,4 +294,44 @@ public class PlanningTabViewModelTests
         Assert.Single(sessions.GetByGroup(groupId));
         Assert.Equal("Für diese Stunde existiert bereits eine Sitzung.", notified);
     }
+
+    [Fact]
+    public void CreateParticipationSession_AndereStundeAmSelbenTagBereitsVerknuepft_LegtKeineZweiteSitzungAn()
+    {
+        // Nutzer-Feedback: eine dritte Stunde am selben Tag (z.B. Vertretung) soll die bereits
+        // bestehende Sitzung des Tages weiterverwenden statt eine zweite anzulegen.
+        var groupId = Guid.NewGuid();
+        var group = new LearningGroup { Id = groupId, Name = "Testgruppe" };
+        var groups = new FakeGroups([group]);
+        var units = new FakeUnits();
+        var lessons = new FakeLessons();
+        var sessions = new FakeSessions([]);
+        var vm = new PlanningTabViewModel(units, lessons, groups, new FakeSubjects([]),
+            new FakeCompetencyDomains(), TestSupport.BuildAiSettingsService(), sessions);
+        vm.Initialize(groupId);
+
+        var unit = new Unit { GroupId = groupId, Title = "Optik" };
+        units.Add(unit);
+        var date = new DateOnly(2025, 9, 1);
+        var doubleLesson = new Lesson
+        { UnitId = unit.Id, GroupId = groupId, Date = date, Topic = "Brechung" };
+        var thirdLesson = new Lesson
+        { UnitId = unit.Id, GroupId = groupId, Date = date, Topic = "Vertretung" };
+        lessons.Add(doubleLesson);
+        lessons.Add(thirdLesson);
+
+        vm.RefreshPlanning(unit.Id, doubleLesson.Id);
+        vm.SelectedLesson = vm.Lessons.Single(l => l.Id == doubleLesson.Id);
+        vm.CreateParticipationSessionCommand.Execute(null);
+
+        string? notified = null;
+        vm.OnNotify = m => notified = m;
+        vm.RefreshPlanning(unit.Id, thirdLesson.Id);
+        vm.SelectedLesson = vm.Lessons.Single(l => l.Id == thirdLesson.Id);
+        vm.CreateParticipationSessionCommand.Execute(null);
+
+        var created = Assert.Single(sessions.GetByGroup(groupId));
+        Assert.Equal(doubleLesson.Id, created.LessonId);
+        Assert.Equal("Für diesen Tag existiert bereits eine Sitzung.", notified);
+    }
 }

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/SeatingPlanViewModelTests.cs

@@ -256,6 +256,30 @@ public sealed class SeatingPlanViewModelTests
         Assert.Single(sessions.GetByGroup(groupId));
     }
 
+    [Fact]
+    public void SelectOrCreateSessionForLesson_AndereStundeAmSelbenTagBereitsVerknuepft_LegtKeineZweiteSitzungAn()
+    {
+        // Nutzer-Feedback: eine dritte Stunde am selben Tag (z.B. durch Vertretung, eigene Lesson-
+        // Id) soll die bereits bestehende Sitzung der Doppelstunde weiterverwenden statt eine
+        // zweite, unabhängige Sitzung für denselben Tag anzulegen.
+        var groupId = Guid.NewGuid();
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var doubleLesson = new Lesson { GroupId = groupId, Date = today, Topic = "Redox" };
+        var thirdLesson = new Lesson { GroupId = groupId, Date = today, Topic = "Vertretung" };
+        var existingSession = new ParticipationSession
+        { GroupId = groupId, Date = today, LessonId = doubleLesson.Id, Comment = "Redox" };
+        var sessions = new FakeSessions([existingSession]);
+        var plan = new SeatingPlan { GroupId = groupId, Name = "Standard", Rows = 1, Columns = 1 };
+        var vm = new SeatingPlanTabViewModel(new FakeSeatingPlans([plan]), new FakeStudents([]),
+            new FakeMemberships([]), sessions, new FakeEntries(), new FakeAspects());
+        vm.Initialize(groupId, isReadOnly: false);
+
+        vm.SelectOrCreateSessionForLesson(thirdLesson);
+
+        Assert.Equal(existingSession.Id, vm.SelectedSession?.Id);
+        Assert.Single(sessions.GetByGroup(groupId));
+    }
+
     [Fact]
     public void SelectOrCreateSessionForLesson_KeineSitzungVorhanden_LegtVerknuepfteAnUndWaehltSieAus()
     {
@@ -472,6 +496,7 @@ 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 +506,56 @@ 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 +592,60 @@ 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()
     {

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/TimetableViewModelTests.cs

@@ -277,7 +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) ────────────────────────────────────────────────
@@ -696,6 +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()
     {

LehrerApp.Desktop/App.axaml

@@ -7,6 +7,17 @@
       <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>
 
@@ -24,5 +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;
@@ -153,6 +154,10 @@ 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.
@@ -170,6 +175,7 @@ public class App : Application
         };
         search.OnQuickAddTask = startAsReminder => ShowQuickTaskDialog(startAsReminder, dash);
         search.OnQuickAddStudent = ShowAddStudentDialog;
+        search.OnQuickAddGroupDocumentation = () => ShowQuickGroupDocumentationDialog(dash);
 
         // StudentList → StudentDetail + Anlegen
         var sl = Services.GetRequiredService<StudentListViewModel>();
@@ -203,4 +209,49 @@ public class App : Application
         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

@@ -16,6 +16,7 @@ using LehrerApp.Sync;
 using LehrerApp.Sync.Crypto;
 using LehrerApp.Sync.Models;
 using Microsoft.Extensions.DependencyInjection;
+using LehrerApp.Templating;
 
 namespace LehrerApp.Desktop;
 
@@ -117,13 +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);
-        backup.CreateBackup(DbPath);
+        var backupSettings = new BackupSettingsService(appData);
+        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));
@@ -187,7 +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) ──────

LehrerApp.Desktop/LehrerApp.Desktop.csproj

@@ -10,6 +10,7 @@
     <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/WebUntisIntegrationService.cs

@@ -5,6 +5,7 @@ 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)
@@ -81,6 +82,10 @@ public sealed class WebUntisIntegrationService(HttpClient http, WebUntisSettings
         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);

LehrerApp.Desktop/Services/WebUntisSettingsService.cs

@@ -13,10 +13,17 @@ internal class WebUntisSettingsConfig
     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
@@ -115,6 +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/ViewModels/ClassTeacher/ClassTeacherOverviewViewModel.cs

@@ -71,19 +71,29 @@ public sealed record ClassTeacherRosterRow(string StudentName, int? ExternKey, b
     };
 
     /// Kumulierte Fehlzeiten seit Schuljahresbeginn (Nutzer-Feedback: der Heute-Snapshot allein
-    /// sagt für Zeugnis/Attestpflicht wenig aus). <see cref="SchoolDaysElapsed"/> zählt nur
-    /// Werktage, ohne Ferienkalender — eine bewusste Vereinfachung, siehe TODO.md 12.4-Nachtrag.
+    /// 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 mit Fehlzeit" +
-        (YearUnexcusedDayCount > 0 ? $" · {YearUnexcusedDayCount} unentschuldigt" : "");
+        $"{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);
@@ -94,7 +104,9 @@ public sealed record ClassTeacherRosterRow(string StudentName, int? ExternKey, b
         IReadOnlyList<UntisForeignClassRegisterEventDto> recentClassRegisterEntries,
         DateOnly? today = null,
         IReadOnlyList<ClassAbsenceDaySummaryRow>? yearAbsences = null,
-        int schoolDaysElapsed = 0)
+        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)
@@ -126,6 +138,8 @@ public sealed record ClassTeacherRosterRow(string StudentName, int? ExternKey, b
                     YearAbsenceDayCount = yearEntries.Count,
                     YearUnexcusedDayCount = yearEntries.Count(r => r.IsUnexcused),
                     SchoolDaysElapsed = schoolDaysElapsed,
+                    HolidayWeekdaysExcluded = holidayWeekdaysExcluded,
+                    TermStart = termStart,
                 };
             })
             .OrderBy(r => r.AttentionRank).ThenBy(r => r.StudentName).ToList();
@@ -157,7 +171,7 @@ public sealed record ClassTeacherTrendDay(string DayLabel, int AlertCount, int U
         $"{UnexcusedCount} unentschuldigt · {LateExcusedCount} verspätet · {ExcusedCount} entschuldigt";
 }
 public sealed record ClassTeacherPatternNotice(string StudentName, string Message,
-    ClassTeacherStatusKind Kind)
+    ClassTeacherStatusKind Kind, bool CanCreateReminder = false)
 {
     public bool IsDangerStatus => Kind == ClassTeacherStatusKind.Danger;
     public bool IsWarningStatus => Kind == ClassTeacherStatusKind.Warning;
@@ -182,7 +196,10 @@ public sealed record ClassTeacherOpenExcuseRow(string StudentName, DateOnly Date
 
     public static IReadOnlyList<ClassTeacherOpenExcuseRow> Build(
         IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDays, DateOnly today) =>
-        absenceDays.Where(a => a.IsUnexcused)
+        // 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)
@@ -192,12 +209,14 @@ public sealed record ClassTeacherOpenExcuseRow(string StudentName, DateOnly Date
 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; } = [];
@@ -268,18 +287,21 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
     public Func<Task>? OnNavigateToSettings { get; set; }
     public Func<Task>? OnNavigateToWorkload { get; set; }
 
-    public ClassTeacherOverviewViewModel(WebUntisSettingsService settings,
+    public ClassTeacherOverviewViewModel(WebUntisSettingsService settings, WebUntisIntegrationService untis,
         UntisReportCacheService cache, SchoolYearService schoolYear, IWorkTaskRepository workTasks,
         IStudentRepository students, IParticipationRepository participation,
-        IParticipationSessionRepository participationSessions, ClassTeacherDetailsViewModel detailsTab)
+        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;
     }
 
@@ -325,14 +347,18 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
             var studentsTask = _cache.GetStudentRosterAsync(className);
             var absencesTask = _cache.GetAbsencesAsync(className, yearStart, today);
             var classRegisterTask = _cache.GetClassRegisterEventsAsync(className, sevenDayStart, today);
-            await Task.WhenAll(studentsTask, absencesTask, classRegisterTask);
+            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 weekAbsenceDays = absenceDaysYear.Where(a => a.Date >= sevenDayStart).ToList();
-            var schoolDaysElapsed = CountWeekdays(yearStart, today);
+            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)) Roster.Add(row);
+                         classRegisterTask.Result, today, absenceDaysYear, schoolDaysElapsed,
+                         holidayWeekdaysExcluded, termStart)) Roster.Add(row);
 
             StudentCount = Roster.Count;
             TodayAlertCount = Roster.Count(r => r.HasAbsenceToday);
@@ -343,7 +369,7 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
             UnexcusedAbsenceCount = Roster.Count(r => r.HasAbsenceToday && !r.IsLate && r.IsUnexcused);
             RecentClassRegisterCount = classRegisterTask.Result.Count;
             BuildTrend(absenceDaysYear, trendDays);
-            BuildPatternNotices(weekAbsenceDays);
+            BuildPatternNotices(absenceDaysYear, sevenDayStart);
             BuildWeekdayPatternNotices(absenceDaysYear);
             BuildAttendanceParticipationNotices();
             BuildOpenExcuses(absenceDaysYear, today);
@@ -451,34 +477,123 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
         return days;
     }
 
-    /// Nenner für <see cref="ClassTeacherRosterRow.YearAbsenceRatePercent"/> — Werktage zwischen
-    /// Schuljahresbeginn und heute, ebenfalls ohne Ferienkalender.
-    private static int CountWeekdays(DateOnly start, DateOnly end)
+    /// 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)) count++;
+            if (d.DayOfWeek is not (DayOfWeek.Saturday or DayOfWeek.Sunday) &&
+                !holidays.Any(h => d >= h.Start && d <= h.End))
+                count++;
         return count;
     }
 
-    private void BuildPatternNotices(IReadOnlyList<ClassAbsenceDaySummaryRow> absenceDays)
+    /// 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()
     {
-        foreach (var group in absenceDays.GroupBy(row => UntisNameMatching.NameKey(row.StudentName)))
+        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 = Roster.FirstOrDefault(row =>
-                UntisNameMatching.NameKey(row.StudentName) == group.Key)?.StudentName ?? rows[0].StudentDisplayName;
-            var lateDays = rows.Count(row => row.IsLate);
-            var unexcusedDays = rows.Count(row => row.IsUnexcused && !row.IsLate);
-            if (unexcusedDays >= 2)
-                PatternNotices.Add(new ClassTeacherPatternNotice(displayName,
-                    $"{unexcusedDays} unentschuldigte Fehltage in 7 Tagen", ClassTeacherStatusKind.Danger));
-            else if (lateDays >= 2)
-                PatternNotices.Add(new ClassTeacherPatternNotice(displayName,
-                    $"{lateDays}-mal verspätet in 7 Tagen", ClassTeacherStatusKind.Warning));
+            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));
         }
-        OnPropertyChanged(nameof(HasPatternNotices));
+        return notices;
     }
 
     /// Erweiterte Mustererkennung (Nutzer-Feedback): die obigen Regeln schauen nur auf die letzten
@@ -635,6 +750,13 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
             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

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");
@@ -105,6 +129,8 @@ 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;
@@ -126,7 +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;
@@ -136,6 +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;
@@ -196,7 +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,
@@ -208,6 +236,8 @@ 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);
@@ -227,6 +257,8 @@ public partial class DashboardViewModel : ObservableObject
         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;
 
@@ -300,12 +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
-                    ? ((DateOnly?)session.Date, e.Attendance) : (null, e.Attendance))
+                .Select(e => sessionDates.TryGetValue(e.SessionId, out var date)
+                    ? ((DateOnly?)date, e.Attendance) : (null, e.Attendance))
                 .Where(t => t.Item1.HasValue)
                 .Select(t => (t.Item1!.Value, t.Attendance));
 
@@ -317,6 +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)
@@ -542,7 +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()
@@ -592,6 +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();
@@ -749,9 +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]
@@ -891,7 +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) ────────────────────────
 
@@ -929,6 +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

LehrerApp.Desktop/ViewModels/Exams/ExamsOverviewViewModel.cs

@@ -43,6 +43,8 @@ public partial class ExamsOverviewViewModel : ObservableObject
     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,
@@ -85,6 +87,7 @@ public partial class ExamsOverviewViewModel : ObservableObject
             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();
@@ -173,6 +176,9 @@ public partial class ExamsOverviewViewModel : ObservableObject
         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);

LehrerApp.Desktop/ViewModels/GlobalSearchViewModel.cs

@@ -17,6 +17,7 @@ public partial class GlobalSearchViewModel : ObservableObject
 
     private readonly IStudentRepository _students;
     private readonly IGroupRepository _groups;
+    private readonly ISubjectRepository _subjects;
     private readonly IExamRepository _exams;
     private readonly IWorkTaskRepository _tasks;
 
@@ -30,13 +31,15 @@ public partial class GlobalSearchViewModel : ObservableObject
     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,
-        IExamRepository exams, IWorkTaskRepository tasks)
+        ISubjectRepository subjects, IExamRepository exams, IWorkTaskRepository tasks)
     {
         _students = students;
         _groups = groups;
+        _subjects = subjects;
         _exams = exams;
         _tasks = tasks;
         RefreshResults();
@@ -59,23 +62,34 @@ public partial class GlobalSearchViewModel : ObservableObject
 
         if (query.Length > 0)
         {
-            var groups = _groups.GetAll(includeInactive: true);
+            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(includeInactive: true)
+            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($"{g.Name} {g.SchoolYear} {g.GradeLevel}", query))
-                .Select(GlobalSearchResult.ForGroup));
+                .Where(g => Matches($"{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) ?? "")));
 
@@ -99,6 +113,7 @@ public partial class GlobalSearchViewModel : ObservableObject
             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)))
@@ -124,6 +139,9 @@ public partial class GlobalSearchViewModel : ObservableObject
             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;
@@ -134,7 +152,7 @@ public partial class GlobalSearchViewModel : ObservableObject
 }
 
 public enum GlobalSearchResultKind { Action, Student, Group, Exam, Task }
-public enum GlobalSearchAction { None, NewTask, NewReminder, NewStudent }
+public enum GlobalSearchAction { None, NewTask, NewReminder, NewStudent, NewGroupDocumentation }
 
 public sealed class GlobalSearchResult
 {
@@ -171,10 +189,13 @@ public sealed class GlobalSearchResult
         Title = student.FullName, Subtitle = student.IsActive ? "Aktiv" : "Inaktiv", Icon = "P",
     };
 
-    public static GlobalSearchResult ForGroup(LearningGroup group) => new()
+    public static GlobalSearchResult ForGroup(LearningGroup group, string subjectName) => new()
     {
         Kind = GlobalSearchResultKind.Group, EntityId = group.Id, GroupId = group.Id,
-        Title = group.Name, Subtitle = $"{group.SchoolYear} · Stufe {group.GradeLevel}", Icon = "G",
+        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()

LehrerApp.Desktop/ViewModels/Groups/ExamViewModels.cs

@@ -32,6 +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;
@@ -108,6 +109,7 @@ public partial class ExamDialogViewModel : ObservableObject
         }
         foreach (var t in Tasks) t.ShowWeight = UseWeighting;
         RecomputeTotals();
+        UpdateWeekLoadHint();
     }
 
     partial void OnUseWeightingChanged(bool value)
@@ -115,6 +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()
     {

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,
-        IStudentRepository students, IDocumentationRepository documentation, IWorkTaskRepository tasks,
-        AttendanceBalanceService attendanceBalance, SchoolYearService schoolYear)
+        IExamResultRepository examResults, IParticipationSessionRepository sessions,
+        IParticipationRepository entries, IStudentRepository students,
+        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/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;
-        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);
+        new LessonSchedulingService(_lessons).Move(moved, newDate, newPeriod, shiftFollowing);
     }
 
     [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();
     }
@@ -375,16 +364,25 @@ public partial class PlanningTabViewModel : ObservableObject
     /// Übernimmt Datum + Thema der Stunde in eine neue Mitarbeitssitzung (3.3.1) — verknüpft über
     /// das bisher ungenutzte Lesson.LessonId-Feld auf ParticipationSession, damit ein zweiter Klick
     /// auf dieselbe Stunde keine doppelte Sitzung anlegt, sondern nur darauf hinweist.
+    ///
+    /// Prüft dabei zusätzlich auf JEDE bereits an diesem Tag bestehende Sitzung, nicht nur eine
+    /// exakt mit `lesson.Id` verknüpfte (Nutzer-Feedback, analog
+    /// <see cref="SeatingPlanTabViewModel.SelectOrCreateSessionForLesson"/>): kommt neben einer
+    /// Doppelstunde noch eine dritte Stunde desselben Tages hinzu (eigene `Lesson`, z.B. durch
+    /// Vertretung), soll das nicht zu einer zweiten Mitarbeitssitzung für den Tag führen.
     [RelayCommand(CanExecute = nameof(HasSelectedLesson))]
     private void CreateParticipationSession()
     {
         if (SelectedLesson is null) return;
         var lesson = SelectedLesson.Model;
-        var existing = _participationSessions.GetByGroup(lesson.GroupId)
-            .FirstOrDefault(s => s.LessonId == lesson.Id);
+        var sessionsForGroup = _participationSessions.GetByGroup(lesson.GroupId);
+        var existing = sessionsForGroup.FirstOrDefault(s => s.LessonId == lesson.Id)
+            ?? sessionsForGroup.FirstOrDefault(s => s.Date == lesson.Date);
         if (existing is not null)
         {
-            OnNotify?.Invoke("Für diese Stunde existiert bereits eine Sitzung.");
+            OnNotify?.Invoke(existing.LessonId == lesson.Id
+                ? "Für diese Stunde existiert bereits eine Sitzung."
+                : "Für diesen Tag existiert bereits eine Sitzung.");
             return;
         }
 
@@ -479,8 +477,14 @@ public class LessonSummary
         Topic = l.Topic;
         StartTimeDisplay = l.StartTime?.ToString("HH:mm") ?? "–";
         Status = l.Status;
-        StatusLabel = l.Status == LessonStatus.Conducted ? "Durchgeführt" : "Geplant";
-        StatusColorHex = l.Status == LessonStatus.Conducted ? "#43A047" : "#9E9E9E";
+        StatusLabel = LessonStatusDisplay.ToName(l.Status);
+        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 +519,23 @@ 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) =>
-        name == "Durchgeführt" ? LessonStatus.Conducted : LessonStatus.Planned;
+    public static LessonStatus FromName(string? name) => name switch
+    {
+        "Entwurf" => LessonStatus.Draft,
+        "Bereit" => LessonStatus.Ready,
+        "Durchgeführt" => LessonStatus.Conducted,
+        _ => LessonStatus.Planned,
+    };
 }
 
 // ── Dialog: Einheit anlegen / bearbeiten (4.1.2 / 4.1.3) ─────────────────────
@@ -722,7 +737,8 @@ 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 +776,12 @@ 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 +1164,45 @@ 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

@@ -141,10 +141,18 @@ public partial class SeatingPlanTabViewModel : ObservableObject
     /// erlaubt: welche Stunde gemeint ist, steht durch die explizite Auswahl der Lehrkraft
     /// (Klick auf "Unterrichtsmodus starten" für genau diese Stunde) bereits unzweideutig fest -
     /// keine Geistersitzungs-Gefahr wie beim bloßen Öffnen eines Tabs.
+    ///
+    /// Fällt bewusst auf JEDE an diesem Tag bereits bestehende Sitzung zurück, nicht nur auf eine
+    /// exakt mit `lesson.Id` verknüpfte (Nutzer-Feedback): kommt neben einer Doppelstunde noch eine
+    /// dritte Stunde am selben Tag hinzu (z.B. Vertretung, eigene `Lesson` mit eigener Id), soll
+    /// keine zweite Mitarbeitssitzung für denselben Tag entstehen — die Lehrkraft passt stattdessen
+    /// die Einschätzung der bereits bestehenden Sitzung an. Das entspricht dem Verhalten von
+    /// <see cref="EnsureTodaySession"/>, das schon immer pro Tag statt pro Stunde arbeitet.
     /// </summary>
     public void SelectOrCreateSessionForLesson(Lesson lesson)
     {
-        var existing = TodaySessions.FirstOrDefault(s => s.LessonId == lesson.Id);
+        var existing = TodaySessions.FirstOrDefault(s => s.LessonId == lesson.Id)
+            ?? TodaySessions.FirstOrDefault(s => s.Date == lesson.Date);
         if (existing is not null) { SelectedSession = existing; return; }
         if (!IsEditable) return;
 
@@ -227,7 +235,7 @@ 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();
@@ -266,6 +274,22 @@ 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 ||
@@ -531,9 +555,13 @@ 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;
@@ -555,10 +583,13 @@ 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;
@@ -570,10 +601,18 @@ 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));
@@ -615,12 +654,16 @@ 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));
     }
 }
 
@@ -646,6 +689,7 @@ 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; }
@@ -656,6 +700,7 @@ 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,
@@ -690,11 +735,15 @@ 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);
     }
@@ -727,6 +776,17 @@ 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;
@@ -793,6 +853,17 @@ 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;
@@ -823,13 +894,23 @@ 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;
     }
 }
 
@@ -847,11 +928,22 @@ 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();
@@ -864,10 +956,13 @@ 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)
@@ -918,6 +1013,17 @@ 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/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;
@@ -108,6 +109,8 @@ public partial class TimetableViewModel : ObservableObject
     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
@@ -301,9 +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));
         }
@@ -353,15 +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,
-    /// aber noch keine konkrete Stunde geplant) bleibt es bei der bisherigen, gröberen Navigation
-    /// 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).
+    /// — sofern für den Slot schon eine Lesson existiert. Ohne Lesson startet die Direktanlage;
+    /// der vorgeschaltete Einheiten-Dialog löst dabei die notwendige Unit-Zuordnung explizit.
     [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);
     }
 
@@ -380,7 +383,7 @@ public partial class TimetableViewModel : ObservableObject
     /// 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 immer alle vier Ziele explizit an, unabhängig von dieser Automatik.
+    /// daneben die weiteren Ziele (einschließlich Anlegen/Verschieben) explizit an.
     [RelayCommand]
     private async Task OpenWeekCell(WeekCellItem? item)
     {
@@ -391,6 +394,8 @@ public partial class TimetableViewModel : ObservableObject
                 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);
     }
 
@@ -399,16 +404,20 @@ public partial class TimetableViewModel : ObservableObject
     /// 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 bewusst das Datum der Lesson selbst statt WeekCellItem.Date entgegen — Date ist dort
-    /// nur bei Kopfzeilen (WeekdayHeader) gesetzt, nicht bei regulären Stunden-Kacheln (ForSlot).
+    /// 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;
-        var now = TimeOnly.FromDateTime(nowSnapshot);
-        return now >= times.Start.Add(-TeachingTimeTolerance) && now <= times.End.Add(TeachingTimeTolerance);
+        // 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]
@@ -487,14 +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,
@@ -560,6 +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
@@ -824,7 +867,9 @@ public partial class WeekCellItem : ObservableObject
     /// Grundlage für den Direktsprung in den Verlaufsplan-Viewer (4.5.2).
     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 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;
@@ -879,18 +924,28 @@ public partial class WeekCellItem : ObservableObject
         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,
@@ -937,12 +992,13 @@ public class UpcomingExamItem(DateOnly date, string groupName, string title)
     public string Title { get; } = title;
 }
 
-public enum TimetableLessonDestination { TeachingMode, Viewer, SeatingPlan, Planning }
+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; } = "";
@@ -960,23 +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/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";
+}

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

@@ -0,0 +1,251 @@
+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
+{
+    // ── Kompetenzkatalog ──────────────────────────────────────────────────────
+
+    [ObservableProperty] private SubjectListItem? _catalogSubject;
+    [ObservableProperty] private int              _catalogGradeLevel = 10;
+    [ObservableProperty] private string           _newDomainName     = "";
+    [ObservableProperty] private string           _newDomainCode     = "";
+    [ObservableProperty] private string           _catalogValidation = "";
+
+    public ObservableCollection<DomainEditItem> Domains { get; } = [];
+
+    // ── Katalog: Laden ────────────────────────────────────────────────────────
+
+    partial void OnCatalogSubjectChanged(SubjectListItem? value)  => LoadCatalog();
+    partial void OnCatalogGradeLevelChanged(int value)            => LoadCatalog();
+
+    private void LoadCatalog()
+    {
+        Domains.Clear();
+        CatalogValidation = "";
+        if (CatalogSubject is null) return;
+        foreach (var d in _domainRepo.GetBySubjectAndGrade(CatalogSubject.Id, CatalogGradeLevel))
+            Domains.Add(CreateDomainEditItem(d));
+        RefreshDomainMoveState();
+    }
+
+    // ── Katalog: Bereich hinzufügen / löschen ────────────────────────────────
+
+    [RelayCommand]
+    private void AddDomain()
+    {
+        if (CatalogSubject is null) { CatalogValidation = "Bitte zuerst ein Fach auswählen."; return; }
+        if (string.IsNullOrWhiteSpace(NewDomainName)) { CatalogValidation = "Bereichsname erforderlich."; return; }
+
+        var domain = new CompetencyDomain
+        {
+            SubjectId  = CatalogSubject.Id,
+            GradeLevel = CatalogGradeLevel,
+            Name       = NewDomainName.Trim(),
+            Code       = NewDomainCode.Trim(),
+            SortOrder  = Domains.Count,
+        };
+        _domainRepo.Save(domain);
+        Domains.Add(CreateDomainEditItem(domain));
+        RefreshDomainMoveState();
+        NewDomainName = ""; NewDomainCode = ""; CatalogValidation = "";
+    }
+
+    [RelayCommand]
+    private void DeleteDomain(DomainEditItem? item)
+    {
+        if (item is null) return;
+        _domainRepo.Delete(item.Id);
+        Domains.Remove(item);
+        PersistDomainOrder();
+    }
+
+    private DomainEditItem CreateDomainEditItem(CompetencyDomain domain) =>
+        new(domain, _domainRepo, item => MoveDomain(item, -1), item => MoveDomain(item, 1));
+
+    private void MoveDomain(DomainEditItem item, int offset)
+    {
+        var oldIndex = Domains.IndexOf(item);
+        var newIndex = oldIndex + offset;
+        if (oldIndex < 0 || newIndex < 0 || newIndex >= Domains.Count) return;
+        Domains.Move(oldIndex, newIndex);
+        PersistDomainOrder();
+    }
+
+    private void PersistDomainOrder()
+    {
+        for (var i = 0; i < Domains.Count; i++) Domains[i].SetSortOrder(i);
+        RefreshDomainMoveState();
+    }
+
+    private void RefreshDomainMoveState()
+    {
+        for (var i = 0; i < Domains.Count; i++)
+            Domains[i].SetMoveState(i > 0, i < Domains.Count - 1);
+    }
+}
+
+// ── DomainEditItem ────────────────────────────────────────────────────────────
+
+public partial class DomainEditItem : ObservableObject
+{
+    private readonly CompetencyDomain            _domain;
+    private readonly ICompetencyDomainRepository _repo;
+
+    public Guid   Id          { get; }
+    public string Name        { get; }
+    public string Code        { get; }
+    public string DisplayName { get; }
+
+    [ObservableProperty] private string _newItemCode = "";
+    [ObservableProperty] private string _newItemDesc = "";
+
+    public ObservableCollection<CompetencyItemVm> Items { get; } = [];
+    public IRelayCommand MoveUpCommand { get; }
+    public IRelayCommand MoveDownCommand { get; }
+
+    public DomainEditItem(CompetencyDomain domain, ICompetencyDomainRepository repo,
+        Action<DomainEditItem>? onMoveUp = null, Action<DomainEditItem>? onMoveDown = null)
+    {
+        _domain     = domain;
+        _repo       = repo;
+        Id          = domain.Id;
+        Name        = domain.Name;
+        Code        = domain.Code;
+        DisplayName = string.IsNullOrEmpty(domain.Code)
+            ? domain.Name
+            : $"{domain.Name}  ({domain.Code})";
+
+        MoveUpCommand = new RelayCommand(() => onMoveUp?.Invoke(this), () => _canMoveUp);
+        MoveDownCommand = new RelayCommand(() => onMoveDown?.Invoke(this), () => _canMoveDown);
+
+        _domain.Items = domain.Items.OrderBy(i => i.SortOrder).ToList();
+        foreach (var item in _domain.Items)
+            Items.Add(CreateItemViewModel(item));
+        RefreshItemMoveState();
+    }
+
+    private bool _canMoveUp;
+    private bool _canMoveDown;
+
+    internal void SetMoveState(bool canMoveUp, bool canMoveDown)
+    {
+        _canMoveUp = canMoveUp;
+        _canMoveDown = canMoveDown;
+        MoveUpCommand.NotifyCanExecuteChanged();
+        MoveDownCommand.NotifyCanExecuteChanged();
+    }
+
+    internal void SetSortOrder(int sortOrder)
+    {
+        if (_domain.SortOrder == sortOrder) return;
+        _domain.SortOrder = sortOrder;
+        _repo.Save(_domain);
+    }
+
+    [RelayCommand]
+    private void AddItem()
+    {
+        if (string.IsNullOrWhiteSpace(NewItemDesc)) return;
+        var item = new CompetencyItem
+        {
+            Code        = NewItemCode.Trim(),
+            Description = NewItemDesc.Trim(),
+            SortOrder   = _domain.Items.Count,
+        };
+        _domain.Items.Add(item);
+        _repo.Save(_domain);
+        Items.Add(CreateItemViewModel(item));
+        RefreshItemMoveState();
+        NewItemCode = ""; NewItemDesc = "";
+    }
+
+    private void DeleteItem(CompetencyItemVm vm)
+    {
+        _domain.Items.RemoveAll(i => i.Id == vm.ItemId);
+        Items.Remove(vm);
+        PersistItemOrder();
+    }
+
+    private CompetencyItemVm CreateItemViewModel(CompetencyItem item) =>
+        new(item, DeleteItem, vm => MoveItem(vm, -1), vm => MoveItem(vm, 1));
+
+    private void MoveItem(CompetencyItemVm item, int offset)
+    {
+        var oldIndex = Items.IndexOf(item);
+        var newIndex = oldIndex + offset;
+        if (oldIndex < 0 || newIndex < 0 || newIndex >= Items.Count) return;
+        Items.Move(oldIndex, newIndex);
+        PersistItemOrder();
+    }
+
+    private void PersistItemOrder()
+    {
+        _domain.Items = Items.Select(x => x.Model).ToList();
+        for (var i = 0; i < _domain.Items.Count; i++) _domain.Items[i].SortOrder = i;
+        _repo.Save(_domain);
+        RefreshItemMoveState();
+    }
+
+    private void RefreshItemMoveState()
+    {
+        for (var i = 0; i < Items.Count; i++)
+            Items[i].SetMoveState(i > 0, i < Items.Count - 1);
+    }
+}
+
+// ── CompetencyItemVm ──────────────────────────────────────────────────────────
+
+public class CompetencyItemVm
+{
+    internal CompetencyItem Model { get; }
+    public Guid   ItemId  { get; }
+    public string Code    { get; }
+    public string Description { get; }
+    public string Display { get; }
+    public IRelayCommand DeleteCommand { get; }
+    public IRelayCommand MoveUpCommand { get; }
+    public IRelayCommand MoveDownCommand { get; }
+
+    public CompetencyItemVm(CompetencyItem item, Action<CompetencyItemVm> onDelete,
+        Action<CompetencyItemVm>? onMoveUp = null, Action<CompetencyItemVm>? onMoveDown = null)
+    {
+        Model       = item;
+        ItemId      = item.Id;
+        Code        = item.Code;
+        Description = item.Description;
+        Display     = string.IsNullOrEmpty(item.Code)
+            ? item.Description
+            : $"[{item.Code}]  {item.Description}";
+        DeleteCommand = new RelayCommand(() => onDelete(this));
+        MoveUpCommand = new RelayCommand(() => onMoveUp?.Invoke(this), () => _canMoveUp);
+        MoveDownCommand = new RelayCommand(() => onMoveDown?.Invoke(this), () => _canMoveDown);
+    }
+
+    private bool _canMoveUp;
+    private bool _canMoveDown;
+
+    internal void SetMoveState(bool canMoveUp, bool canMoveDown)
+    {
+        _canMoveUp = canMoveUp;
+        _canMoveDown = canMoveDown;
+        MoveUpCommand.NotifyCanExecuteChanged();
+        MoveDownCommand.NotifyCanExecuteChanged();
+    }
+}
+
+// ── GradingKeyTemplateEditItem (1.3.2) ─────────────────────────────────────────

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

@@ -0,0 +1,111 @@
+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
+{
+    // ── Geräte-Pairing (10.3.1: Schlüsselübertragung auf ein zweites Gerät) ───
+    //
+    // SnapshotService ist nur registriert, wenn bereits eine Server-URL konfiguriert ist (siehe
+    // AppBootstrapper) — daher optional/nullable statt eines Pflicht-Konstruktorparameters.
+
+    [ObservableProperty] private string _pairingCode = "";
+    [ObservableProperty] private string _pairingCodeInput = "";
+    [ObservableProperty] private string _pairingStatus = "";
+    [ObservableProperty] private bool   _pairingBusy;
+
+    /// Vom Code-Behind gesetzt: zeigt einen Bestätigungsdialog, bevor die lokale Datenbank durch
+    /// den Stand des anderen Geräts ersetzt wird.
+    public Func<Task<bool>>? OnConfirmPairingRestore { get; set; }
+
+    /// Vom Code-Behind gesetzt: zeigt einen Fehlerdialog, den der Nutzer aktiv wegklicken muss —
+    /// notwendig, weil RedeemPairingCode() nach einem Fehlschlag sofort neu startet (_dbContext ist
+    /// zu dem Zeitpunkt bereits disposed, siehe dort) und PairingStatus dadurch sonst nie sichtbar
+    /// gerendert würde.
+    public Func<string, Task>? OnShowPairingError { get; set; }
+
+    // ── Geräte-Pairing: Code erzeugen / einlösen ─────────────────────────────
+    //
+    // CreateAndUploadAsync lädt einen verschlüsselten Snapshot der lokalen Datenbank samt
+    // Sync-Schlüssel hoch, RestoreFromCodeAsync ersetzt auf dem ZWEITEN Gerät die dortige
+    // Datenbank vollständig durch diesen Snapshot (vorheriger Stand wird automatisch als
+    // .backup-Datei gesichert, siehe SnapshotService) — deshalb vor dem Einlösen ein
+    // Bestätigungsdialog wie bei RestoreBackup.
+
+    [RelayCommand]
+    private async Task CreatePairingCode()
+    {
+        if (_snapshotService is null) return;
+        PairingBusy = true;
+        PairingCode = "";
+        PairingStatus = "";
+        void OnProgress(SnapshotProgress p) => PairingStatus = p.Message;
+        _snapshotService.ProgressChanged += OnProgress;
+        try
+        {
+            var result = await _snapshotService.CreateAndUploadAsync();
+            PairingCode = result.Code;
+            PairingStatus = $"Gültig bis {result.ExpiresAt:dd.MM.yyyy HH:mm} — auf dem anderen Gerät eingeben.";
+        }
+        catch (Exception ex) when (ex is HttpRequestException or InvalidOperationException)
+        {
+            PairingStatus = $"Fehlgeschlagen: {ex.Message}";
+        }
+        finally
+        {
+            _snapshotService.ProgressChanged -= OnProgress;
+            PairingBusy = false;
+        }
+    }
+
+    [RelayCommand]
+    private async Task RedeemPairingCode()
+    {
+        if (_snapshotService is null) return;
+        if (string.IsNullOrWhiteSpace(PairingCodeInput)) { PairingStatus = "Bitte Code eingeben."; return; }
+        if (OnConfirmPairingRestore is not null && !await OnConfirmPairingRestore()) return;
+
+        PairingBusy = true;
+        PairingStatus = "";
+        void OnProgress(SnapshotProgress p) => PairingStatus = p.Message;
+        _snapshotService.ProgressChanged += OnProgress;
+
+        // LiteDB hält beim Öffnen einen exklusiven Dateilock — muss vor dem Überschreiben
+        // geschlossen sein. Läuft danach ein Fehler (falscher Code, Server nicht erreichbar), ist
+        // _dbContext bereits disposed und die App nicht mehr sicher weiter benutzbar, ohne dass
+        // die Datenbankdatei selbst angefasst wurde (RestoreFromCodeAsync schreibt sie erst ganz
+        // am Ende) — deshalb in JEDEM Fall (Erfolg wie Fehlschlag) neu starten, nicht nur bei
+        // Erfolg. Ein Neustart öffnet dann wieder dieselbe, unveränderte Datenbank.
+        _dbContext.Dispose();
+        try
+        {
+            await _snapshotService.RestoreFromCodeAsync(PairingCodeInput.Trim(), AppBootstrapper.DbPath);
+        }
+        catch (Exception ex) when (ex is SnapshotNotFoundException or InvalidOperationException or HttpRequestException)
+        {
+            // _dbContext ist bereits disposed, PairingStatus ist aber ein reines ViewModel-Feld
+            // ohne DB-Zugriff - das Setzen ist unabhängig davon noch sicher.
+            PairingStatus = $"Fehlgeschlagen: {ex.Message}";
+            _logger.Error("Geräte-Pairing (Redeem) fehlgeschlagen", ex);
+            // Ohne diesen Dialog würde PairingStatus nie gerendert: der direkt folgende Neustart
+            // (unten, auch im Fehlerfall nötig, siehe Kommentar oben) beendet den Prozess, bevor
+            // Avalonia den nächsten Frame zeichnen könnte.
+            if (OnShowPairingError is not null) await OnShowPairingError(ex.Message);
+        }
+        AppBootstrapper.RestartApplication();
+    }
+}

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

@@ -0,0 +1,85 @@
+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: Datenbank-Verschlüsselung (13.3.4) ───────────────────────
+
+    [ObservableProperty] private bool   _isDbEncrypted;
+    [ObservableProperty] private string _currentDbPassword    = "";
+    [ObservableProperty] private string _newDbPassword        = "";
+    [ObservableProperty] private string _newDbPasswordConfirm = "";
+    [ObservableProperty] private string _dbPasswordError      = "";
+
+    public string DbEncryptionStatusLabel => IsDbEncrypted ? "verschlüsselt" : "nicht verschlüsselt";
+
+    partial void OnIsDbEncryptedChanged(bool value) => OnPropertyChanged(nameof(DbEncryptionStatusLabel));
+
+    // ── Datenbank-Verschlüsselung: Setzen / Ändern / Entfernen ───────────────
+
+    [RelayCommand]
+    private void SaveDbPassword()
+    {
+        DbPasswordError = "";
+        var valid = true;
+        var wantsPassword = !string.IsNullOrWhiteSpace(NewDbPassword) || !string.IsNullOrWhiteSpace(NewDbPasswordConfirm);
+
+        if (IsDbEncrypted && !_dbEncryption.VerifyPassword(AppBootstrapper.DbPath, CurrentDbPassword))
+        {
+            DbPasswordError = "Aktuelles Passwort ist falsch.";
+            valid = false;
+        }
+
+        if (!wantsPassword)
+        {
+            DbPasswordError = "Bitte ein neues Passwort eingeben.";
+            valid = false;
+        }
+        else if (NewDbPassword != NewDbPasswordConfirm)
+        {
+            DbPasswordError = "Neue Passwörter stimmen nicht überein.";
+            valid = false;
+        }
+        else if (NewDbPassword.Length < 4)
+        {
+            DbPasswordError = "Mindestens 4 Zeichen.";
+            valid = false;
+        }
+
+        if (!valid) return;
+
+        _dbContext.Dispose();
+        _dbEncryption.SetPassword(AppBootstrapper.DbPath, IsDbEncrypted ? CurrentDbPassword : null, NewDbPassword.Trim());
+        AppBootstrapper.RestartApplication();
+    }
+
+    [RelayCommand]
+    private void RemoveDbPassword()
+    {
+        DbPasswordError = "";
+        if (!_dbEncryption.VerifyPassword(AppBootstrapper.DbPath, CurrentDbPassword))
+        {
+            DbPasswordError = "Aktuelles Passwort ist falsch.";
+            return;
+        }
+
+        _dbContext.Dispose();
+        _dbEncryption.SetPassword(AppBootstrapper.DbPath, CurrentDbPassword, null);
+        AppBootstrapper.RestartApplication();
+    }
+}

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

@@ -0,0 +1,154 @@
+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
+{
+    // ── Notenschlüssel-Vorlagen (1.3.2) ──────────────────────────────────────
+
+    [ObservableProperty] private string _newTemplateName = "";
+    [ObservableProperty] private string _newTemplateGradingSystemName = "Noten 1–6";
+    [ObservableProperty] private string _newTemplateNameError = "";
+
+    public List<string> GradingSystemOptions { get; } = ["Noten 1–6", "Punkte 0–15"];
+    public ObservableCollection<GradingKeyTemplateEditItem> GradingKeyTemplateList { get; } = [];
+
+    // ── Notenschlüssel-Vorlagen: Laden / Hinzufügen / Löschen ────────────────
+
+    private void LoadGradingKeyTemplates()
+    {
+        GradingKeyTemplateList.Clear();
+        foreach (var t in _gradingKeyTemplates.GetAll())
+            GradingKeyTemplateList.Add(new GradingKeyTemplateEditItem(t, _gradingKeyTemplates, _grading));
+    }
+
+    [RelayCommand]
+    private void AddGradingKeyTemplate()
+    {
+        if (string.IsNullOrWhiteSpace(NewTemplateName)) { NewTemplateNameError = "Vorlagenname erforderlich."; return; }
+
+        var system = NewTemplateGradingSystemName == "Punkte 0–15"
+            ? GradingSystem.Points0To15 : GradingSystem.Grades1To6;
+        var defaults = system == GradingSystem.Grades1To6
+            ? GradingService.DefaultKey1To6() : GradingService.DefaultKey0To15();
+
+        var template = new GradingKeyTemplate
+        {
+            Name = NewTemplateName.Trim(),
+            GradingSystem = system,
+            Entries = defaults.Select(e => new GradingKeyEntry { Grade = e.Grade, MinPercent = e.MinPercent }).ToList(),
+        };
+        _gradingKeyTemplates.Save(template);
+        GradingKeyTemplateList.Add(new GradingKeyTemplateEditItem(template, _gradingKeyTemplates, _grading));
+        NewTemplateName = "";
+        NewTemplateNameError = "";
+    }
+
+    [RelayCommand]
+    private void DeleteGradingKeyTemplate(GradingKeyTemplateEditItem? item)
+    {
+        if (item is null) return;
+        _gradingKeyTemplates.Delete(item.Id);
+        GradingKeyTemplateList.Remove(item);
+    }
+}
+
+public partial class GradingKeyTemplateEditItem : ObservableObject
+{
+    private readonly GradingKeyTemplate _template;
+    private readonly IGradingKeyTemplateRepository _repo;
+    private readonly GradingService _grading;
+
+    public Guid   Id                 { get; }
+    public string Name               { get; }
+    public string GradingSystemLabel { get; }
+
+    [ObservableProperty] private string _newGrade = "";
+    [ObservableProperty] private double _newMinPercent;
+    [ObservableProperty] private string _newGradeError = "";
+    [ObservableProperty] private string _newMinPercentError = "";
+    [ObservableProperty] private string _completenessWarning = "";
+
+    public ObservableCollection<GradingKeyEntryVm> Entries { get; } = [];
+
+    public GradingKeyTemplateEditItem(GradingKeyTemplate template, IGradingKeyTemplateRepository repo,
+        GradingService grading)
+    {
+        _template = template; _repo = repo; _grading = grading;
+        Id   = template.Id;
+        Name = template.Name;
+        GradingSystemLabel = template.GradingSystem == GradingSystem.Grades1To6
+            ? "Noten 1–6" : "Punkte 0–15";
+
+        foreach (var e in template.Entries.OrderByDescending(e => e.MinPercent))
+            Entries.Add(new GradingKeyEntryVm(e, DeleteEntry));
+        RecomputeCompleteness();
+    }
+
+    [RelayCommand]
+    private void AddEntry()
+    {
+        NewGradeError = ""; NewMinPercentError = "";
+        var valid = true;
+
+        if (string.IsNullOrWhiteSpace(NewGrade)) { NewGradeError = "Bezeichnung erforderlich."; valid = false; }
+        if (NewMinPercent is < 0 or > 100) { NewMinPercentError = "Muss zwischen 0 und 100 liegen."; valid = false; }
+        else if (_template.Entries.Any(e => Math.Abs(e.MinPercent - NewMinPercent) < 0.0001))
+        { NewMinPercentError = "Diese Prozentgrenze existiert bereits."; valid = false; }
+
+        if (!valid) return;
+
+        var entry = new GradingKeyEntry { Grade = NewGrade.Trim(), MinPercent = NewMinPercent };
+        _template.Entries.Add(entry);
+        _template.Entries = _template.Entries.OrderByDescending(e => e.MinPercent).ToList();
+        _repo.Save(_template);
+
+        Entries.Clear();
+        foreach (var e in _template.Entries) Entries.Add(new GradingKeyEntryVm(e, DeleteEntry));
+        NewGrade = ""; NewMinPercent = 0;
+        RecomputeCompleteness();
+    }
+
+    private void DeleteEntry(GradingKeyEntryVm vm)
+    {
+        _template.Entries.RemoveAll(e => e.Grade == vm.Grade && Math.Abs(e.MinPercent - vm.MinPercent) < 0.0001);
+        _repo.Save(_template);
+        Entries.Remove(vm);
+        RecomputeCompleteness();
+    }
+
+    private void RecomputeCompleteness() =>
+        CompletenessWarning = _grading.ValidateGradingKey(_template.Entries) ?? "";
+}
+
+// ── GradingKeyEntryVm ─────────────────────────────────────────────────────────
+
+public class GradingKeyEntryVm
+{
+    public string Grade      { get; }
+    public double MinPercent { get; }
+    public string Display    { get; }
+    public IRelayCommand DeleteCommand { get; }
+
+    public GradingKeyEntryVm(GradingKeyEntry e, Action<GradingKeyEntryVm> onDelete)
+    {
+        Grade      = e.Grade;
+        MinPercent = e.MinPercent;
+        Display    = $"{Grade} — ab {MinPercent.ToString("0.##")} %";
+        DeleteCommand = new RelayCommand(() => onDelete(this));
+    }
+}

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

@@ -0,0 +1,146 @@
+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
+{
+    // ── Ferien & Feiertage (4.3.5, aus dem Stundenplan hierher verschoben) ───
+
+    [ObservableProperty] private string _selectedStateName = "";
+    [ObservableProperty] private string _newHolidayName = "";
+    [ObservableProperty] private string _newHolidayStartText = "";
+    [ObservableProperty] private string _newHolidayEndText = "";
+    [ObservableProperty] private string _holidayNameError = "";
+    [ObservableProperty] private string _holidayDateError = "";
+    [ObservableProperty] private string _schoolName = "";
+    [ObservableProperty] private string _schoolStreet = "";
+    [ObservableProperty] private string _schoolPostalCode = "";
+    [ObservableProperty] private string _schoolCity = "";
+    [ObservableProperty] private string _schoolNameError = "";
+    [ObservableProperty] private string _schoolStreetError = "";
+    [ObservableProperty] private string _schoolPostalCodeError = "";
+    [ObservableProperty] private string _schoolCityError = "";
+    [ObservableProperty] private string _schoolLocationStatus = "";
+    [ObservableProperty] private string _resolvedSchoolAddress = "";
+
+    public List<string> StateOptions { get; } = GermanStateDisplay.Options.ToList();
+    public ObservableCollection<SchoolHolidayItem> SchoolHolidayEntries { get; } = [];
+
+    // ── Ferien & Feiertage: Bundesland / Schulferien pflegen ─────────────────
+
+    partial void OnSelectedStateNameChanged(string value) =>
+        _calendarSettings.SetState(GermanStateDisplay.FromLabel(value));
+
+    [RelayCommand]
+    private async Task LoadSchoolLocation()
+    {
+        if (_schoolWeather is null) return;
+        try
+        {
+            var location = await _schoolWeather.GetLocationAsync();
+            if (location is null) return;
+            SchoolName = location.SchoolName;
+            SchoolStreet = location.Street;
+            SchoolPostalCode = location.PostalCode;
+            SchoolCity = location.City;
+            SelectedStateName = GermanStateDisplay.Label(location.State);
+            ResolvedSchoolAddress = location.ResolvedAddress;
+        }
+        catch (SchoolWeatherException ex) { SchoolLocationStatus = ex.Message; }
+    }
+
+    [RelayCommand]
+    private async Task SaveSchoolLocation()
+    {
+        SchoolNameError = ""; SchoolStreetError = ""; SchoolPostalCodeError = "";
+        SchoolCityError = ""; SchoolLocationStatus = "";
+        var valid = true;
+        if (string.IsNullOrWhiteSpace(SchoolName))
+        { SchoolNameError = "Name der Schule erforderlich."; valid = false; }
+        if (string.IsNullOrWhiteSpace(SchoolStreet))
+        { SchoolStreetError = "Straße und Hausnummer erforderlich."; valid = false; }
+        if (!System.Text.RegularExpressions.Regex.IsMatch(SchoolPostalCode.Trim(), @"^\d{5}$"))
+        { SchoolPostalCodeError = "Bitte eine fünfstellige PLZ angeben."; valid = false; }
+        if (string.IsNullOrWhiteSpace(SchoolCity))
+        { SchoolCityError = "Ort erforderlich."; valid = false; }
+        if (!valid) return;
+        if (_schoolWeather is null)
+        {
+            SchoolLocationStatus = "Der Wetterdienst ist nicht verfügbar.";
+            return;
+        }
+
+        SchoolLocationStatus = "Adresse wird geprüft …";
+        try
+        {
+            var profile = await _schoolWeather.SaveLocationAsync(new SchoolLocationRequest
+            {
+                SchoolName = SchoolName.Trim(), Street = SchoolStreet.Trim(),
+                PostalCode = SchoolPostalCode.Trim(), City = SchoolCity.Trim(),
+                State = GermanStateDisplay.FromLabel(SelectedStateName),
+            });
+            ResolvedSchoolAddress = profile.ResolvedAddress;
+            SchoolLocationStatus = "Schulstandort gespeichert. Wetterdaten werden serverseitig abgerufen.";
+        }
+        catch (SchoolWeatherException ex) { SchoolLocationStatus = ex.Message; }
+    }
+
+    private void LoadSchoolHolidays()
+    {
+        SchoolHolidayEntries.Clear();
+        foreach (var h in _schoolHolidays.GetAll().OrderBy(h => h.StartDate))
+            SchoolHolidayEntries.Add(new SchoolHolidayItem(h));
+    }
+
+    [RelayCommand]
+    private void AddSchoolHoliday()
+    {
+        HolidayNameError = ""; HolidayDateError = "";
+        var valid = true;
+
+        if (string.IsNullOrWhiteSpace(NewHolidayName)) { HolidayNameError = "Name erforderlich."; valid = false; }
+
+        var hasStart = DateOnly.TryParseExact(NewHolidayStartText, "dd.MM.yyyy", CultureInfo.InvariantCulture,
+            System.Globalization.DateTimeStyles.None, out var start);
+        var hasEnd = DateOnly.TryParseExact(NewHolidayEndText, "dd.MM.yyyy", CultureInfo.InvariantCulture,
+            System.Globalization.DateTimeStyles.None, out var end);
+
+        if (!hasStart || !hasEnd) { HolidayDateError = "Bitte Beginn und Ende im Format TT.MM.JJJJ angeben."; valid = false; }
+        else if (end < start) { HolidayDateError = "Das Ende darf nicht vor dem Beginn liegen."; valid = false; }
+
+        if (!valid) return;
+
+        _schoolHolidays.Save(new SchoolHoliday { Name = NewHolidayName.Trim(), StartDate = start, EndDate = end });
+        NewHolidayName = ""; NewHolidayStartText = ""; NewHolidayEndText = "";
+        LoadSchoolHolidays();
+    }
+
+    [RelayCommand]
+    private void RemoveSchoolHoliday(SchoolHolidayItem? item)
+    {
+        if (item is null) return;
+        _schoolHolidays.Delete(item.Id);
+        SchoolHolidayEntries.Remove(item);
+    }
+}
+
+public class SchoolHolidayItem(SchoolHoliday h)
+{
+    public Guid   Id           { get; } = h.Id;
+    public string Name         { get; } = h.Name;
+    public string RangeDisplay { get; } = $"{h.StartDate:dd.MM.yyyy} – {h.EndDate:dd.MM.yyyy}";
+}

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

@@ -0,0 +1,123 @@
+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
+{
+    // ── JSON Import / Export ──────────────────────────────────────────────────
+
+    public CompetencyCatalogImportPreview? PrepareCatalogImport(string json)
+    {
+        if (CatalogSubject is null)
+        {
+            CatalogValidation = "Bitte zuerst ein Fach auswählen.";
+            return null;
+        }
+        try
+        {
+            CatalogValidation = "";
+            return _catalogImport.Analyze(
+                json, CatalogSubject.Id, CatalogSubject.Name, CatalogGradeLevel);
+        }
+        catch (InvalidDataException ex)
+        {
+            CatalogValidation = ex.Message;
+            return null;
+        }
+    }
+
+    public void ApplyCatalogImport(CompetencyCatalogImportPreview preview,
+        CompetencyCatalogImportMode mode, IReadOnlySet<string> useImportedConflicts)
+    {
+        _catalogImport.Apply(preview, mode, useImportedConflicts);
+        LoadCatalog();
+        CatalogValidation = mode == CompetencyCatalogImportMode.Merge
+            ? "Kompetenzkatalog wurde sicher zusammengeführt."
+            : "Kompetenzkatalog wurde vollständig ersetzt.";
+    }
+
+    public string ExportCatalog()
+        => SerializeCatalog(CatalogGradeLevel);
+
+    public CompetencyCatalogImportPreview? PrepareCatalogCopy(int targetGradeLevel)
+    {
+        if (CatalogSubject is null)
+        {
+            CatalogValidation = "Bitte zuerst ein Fach auswählen.";
+            return null;
+        }
+        if (Domains.Count == 0)
+        {
+            CatalogValidation = "Der ausgewählte Katalog enthält keine Bereiche.";
+            return null;
+        }
+        if (targetGradeLevel is < 1 or > 13 || targetGradeLevel == CatalogGradeLevel)
+        {
+            CatalogValidation = "Bitte eine andere Zielklassenstufe zwischen 1 und 13 auswählen.";
+            return null;
+        }
+
+        CatalogValidation = "";
+        return _catalogImport.Analyze(SerializeCatalog(targetGradeLevel), CatalogSubject.Id,
+            CatalogSubject.Name, targetGradeLevel);
+    }
+
+    public void SetCatalogCopyStatus(int targetGradeLevel) =>
+        CatalogValidation = $"Kompetenzkatalog wurde in Klassenstufe {targetGradeLevel} kopiert.";
+
+    private string SerializeCatalog(int gradeLevel)
+    {
+        var dto = new CatalogDto
+        {
+            Subject    = CatalogSubject?.Name ?? "",
+            GradeLevel = gradeLevel,
+            Domains    = Domains.Select(d => new DomainDto
+            {
+                Name         = d.Name,
+                Code         = d.Code,
+                Competencies = d.Items.Select(i => new CompetencyDto
+                {
+                    Code        = i.Code,
+                    Description = i.Description,
+                }).ToList(),
+            }).ToList(),
+        };
+        return JsonSerializer.Serialize(dto, new JsonSerializerOptions { WriteIndented = true });
+    }
+}
+
+// ── JSON DTOs ─────────────────────────────────────────────────────────────────
+
+internal class CatalogDto
+{
+    [JsonPropertyName("subject")]    public string?          Subject    { get; set; }
+    [JsonPropertyName("gradeLevel")] public int              GradeLevel { get; set; }
+    [JsonPropertyName("domains")]    public List<DomainDto>? Domains    { get; set; }
+}
+
+internal class DomainDto
+{
+    [JsonPropertyName("name")]          public string?               Name         { get; set; }
+    [JsonPropertyName("code")]          public string?               Code         { get; set; }
+    [JsonPropertyName("competencies")]  public List<CompetencyDto>?  Competencies { get; set; }
+}
+
+internal class CompetencyDto
+{
+    [JsonPropertyName("code")]        public string? Code        { get; set; }
+    [JsonPropertyName("description")] public string? Description { get; set; }
+}

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

@@ -0,0 +1,80 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Templating;
+using System.Collections.ObjectModel;
+
+namespace LehrerApp.Desktop.ViewModels.Settings;
+
+public partial class SettingsViewModel
+{
+    [ObservableProperty] private string _letterTemplateStatus = "";
+    public ObservableCollection<LetterTemplateListItem> LetterTemplateList { get; } = [];
+
+    private void LoadLetterTemplates()
+    {
+        LetterTemplateList.Clear();
+        foreach (var template in _letterTemplates.GetTemplates()) LetterTemplateList.Add(CreateItem(template));
+    }
+
+    public void ImportLetterTemplate(string path)
+    {
+        LetterTemplateStatus = "";
+        try
+        {
+            var template = _letterTemplates.Import(path);
+            LoadLetterTemplates();
+            LetterTemplateStatus = $"„{template.Name}“ wurde geprüft und lokal importiert.";
+        }
+        catch (Exception ex) when (ex is IOException or InvalidDataException or UnauthorizedAccessException or TemplateValidationException)
+        { LetterTemplateStatus = $"Import fehlgeschlagen: {ex.Message}"; }
+    }
+
+    [RelayCommand]
+    private void ValidateLetterTemplate(LetterTemplateListItem? item)
+    {
+        if (item is null) return;
+        try
+        {
+            var refreshed = CreateItem(item.Model);
+            var index = LetterTemplateList.IndexOf(item);
+            if (index >= 0) LetterTemplateList[index] = refreshed;
+            LetterTemplateStatus = $"„{item.Name}“ ist gültig (Schema {refreshed.SchemaVersion}).";
+        }
+        catch (Exception ex) when (ex is IOException or InvalidDataException or TemplateValidationException)
+        { LetterTemplateStatus = $"„{item.Name}“ ist ungültig: {ex.Message}"; }
+    }
+
+    [RelayCommand]
+    private void DeleteLetterTemplate(LetterTemplateListItem? item)
+    {
+        if (item is null) return;
+        _letterTemplates.Delete(item.Id); LetterTemplateList.Remove(item); LetterTemplateStatus = "Vorlage gelöscht.";
+    }
+
+    private LetterTemplateListItem CreateItem(InstalledTemplate template)
+    {
+        var loaded = _letterTemplates.Load(template);
+        return new(template, loaded.Manifest.SchemaVersion, loaded.Manifest.Placeholders.Count(x => !x.IsConstant),
+            loaded.Manifest.Placeholders.Count(x => !x.IsConstant && x.Required));
+    }
+}
+
+public sealed class LetterTemplateListItem(InstalledTemplate model, int schemaVersion, int fieldCount, int requiredCount)
+{
+    public InstalledTemplate Model { get; } = model;
+    public string Id => Model.Id;
+    public string Name => Model.Name;
+    public string PackageFileName => Path.GetFileName(Model.PackagePath);
+    public int SchemaVersion { get; } = schemaVersion;
+    public bool HasIssues => false;
+    public bool HasNoIssues => true;
+    public string ValidationSummary => $"Schema {SchemaVersion} · {fieldCount} Felder ({requiredCount} Pflicht)";
+    public ObservableCollection<LetterTemplateIssueItem> Issues { get; } = [];
+}
+
+public sealed class LetterTemplateIssueItem(ValidationIssue issue)
+{
+    public string Icon => issue.Severity == ValidationSeverity.Error ? "⛔" : "ⓘ";
+    public string Message => issue.Message;
+    public string Color => issue.Severity == ValidationSeverity.Error ? "#DC2626" : "#6B7280";
+}

LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.PeriodSchedule.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
+{
+    // ── Stundenraster: Uhrzeiten je Einzelstunde (4.2.2 Nachtrag) ────────────
+
+    [ObservableProperty] private string _periodTimesError = "";
+    [ObservableProperty] private string _periodTimesStatus = "";
+
+    public ObservableCollection<PeriodTimeEditItem> PeriodTimes { get; } = [];
+
+    // ── Stundenraster: Laden / Speichern ─────────────────────────────────────
+
+    private void LoadPeriodTimes()
+    {
+        PeriodTimes.Clear();
+        for (var period = 1; period <= 10; period++)
+        {
+            var times = _periodSchedule.GetTimes(period);
+            PeriodTimes.Add(new PeriodTimeEditItem(period, times?.Start, times?.End));
+        }
+    }
+
+    [RelayCommand]
+    private void SavePeriodTimes()
+    {
+        PeriodTimesError = ""; PeriodTimesStatus = "";
+        var entries = new List<PeriodTimeEntry>();
+
+        foreach (var item in PeriodTimes)
+        {
+            if (string.IsNullOrWhiteSpace(item.StartText) && string.IsNullOrWhiteSpace(item.EndText))
+                continue; // Stunde bewusst nicht konfiguriert — ok, keine Pflicht für alle 10.
+
+            if (!TimeOnly.TryParseExact(item.StartText, "HH:mm", CultureInfo.InvariantCulture, DateTimeStyles.None, out var start) ||
+                !TimeOnly.TryParseExact(item.EndText, "HH:mm", CultureInfo.InvariantCulture, DateTimeStyles.None, out var end))
+            { PeriodTimesError = $"{item.PeriodLabel}: Format HH:MM."; return; }
+
+            if (end <= start)
+            { PeriodTimesError = $"{item.PeriodLabel}: Ende muss nach dem Beginn liegen."; return; }
+
+            entries.Add(new PeriodTimeEntry { PeriodNumber = item.PeriodNumber, Start = start, End = end });
+        }
+
+        _periodSchedule.SetPeriods(entries);
+        PeriodTimesStatus = "Gespeichert.";
+    }
+}
+
+public partial class PeriodTimeEditItem : ObservableObject
+{
+    public int    PeriodNumber { get; }
+    public string PeriodLabel  { get; }
+
+    [ObservableProperty] private string _startText;
+    [ObservableProperty] private string _endText;
+
+    public PeriodTimeEditItem(int periodNumber, TimeOnly? start, TimeOnly? end)
+    {
+        PeriodNumber = periodNumber;
+        PeriodLabel  = $"{periodNumber}. Stunde";
+        _startText   = start?.ToString("HH:mm") ?? "";
+        _endText     = end?.ToString("HH:mm") ?? "";
+    }
+}

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

@@ -0,0 +1,68 @@
+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
+{
+    // ── Datenschutz: Löschfristen (5.4.2) ────────────────────────────────────
+
+    [ObservableProperty] private int _retentionYears = 3;
+    [ObservableProperty] private string _retentionStatus = "";
+
+    public ObservableCollection<ExpiredDocumentItem> ExpiredDocuments { get; } = [];
+
+    /// Vom Code-Behind gesetzt: zeigt einen Bestätigungsdialog vor dem endgültigen Löschen.
+    public Func<ExpiredDocumentItem, Task<bool>>? OnConfirmHardDelete { get; set; }
+
+    // ── Datenschutz: Löschfristen ─────────────────────────────────────────────
+
+    private void LoadExpiredDocuments()
+    {
+        ExpiredDocuments.Clear();
+        var cutoff = _privacy.RetentionCutoff();
+        foreach (var d in _documentation.GetAll().Where(d => d.CreatedAt < cutoff))
+        {
+            var student = _students.GetById(d.StudentId);
+            ExpiredDocuments.Add(new ExpiredDocumentItem(d, student?.FullName ?? "?"));
+        }
+    }
+
+    [RelayCommand]
+    private void SaveRetentionYears()
+    {
+        _privacy.SetRetentionYears(RetentionYears);
+        LoadExpiredDocuments();
+        RetentionStatus = "Gespeichert.";
+    }
+
+    [RelayCommand]
+    private async Task HardDeleteDocument(ExpiredDocumentItem? item)
+    {
+        if (item is null) return;
+        if (OnConfirmHardDelete is not null && !await OnConfirmHardDelete(item)) return;
+        _documentation.HardDelete(item.Id);
+        ExpiredDocuments.Remove(item);
+    }
+}
+
+public class ExpiredDocumentItem(Documentation d, string studentName)
+{
+    public Guid Id { get; } = d.Id;
+    public string StudentName { get; } = studentName;
+    public string Title { get; } = d.Title;
+    public string CreatedAtDisplay { get; } = d.CreatedAt.ToLocalTime().ToString("dd.MM.yyyy");
+}

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

@@ -0,0 +1,69 @@
+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
+{
+    // ── Kürzel-Katalog (Stundenverlaufsplan, 4.2.2) ──────────────────────────
+
+    [ObservableProperty] private string _newShorthandCode      = "";
+    [ObservableProperty] private string _newShorthandLabel     = "";
+    [ObservableProperty] private string _newShorthandCodeError = "";
+
+    public ObservableCollection<ShorthandCodeListItem> ShorthandCodes { get; } = [];
+
+    // ── Kürzel-Katalog: Laden / Hinzufügen / Löschen ─────────────────────────
+
+    public void LoadShorthandCodes()
+    {
+        ShorthandCodes.Clear();
+        foreach (var c in _shorthandCodes.GetAll())
+            ShorthandCodes.Add(new ShorthandCodeListItem(c));
+    }
+
+    [RelayCommand]
+    private void AddShorthandCode()
+    {
+        if (string.IsNullOrWhiteSpace(NewShorthandCode)) { NewShorthandCodeError = "Kürzel erforderlich."; return; }
+        try
+        {
+            _shorthandCodes.Save(new ShorthandCode { Code = NewShorthandCode.Trim(), Label = NewShorthandLabel.Trim() });
+        }
+        catch (InvalidOperationException ex)
+        {
+            NewShorthandCodeError = ex.Message;
+            return;
+        }
+        NewShorthandCode = ""; NewShorthandLabel = ""; NewShorthandCodeError = "";
+        LoadShorthandCodes();
+    }
+
+    [RelayCommand]
+    private void DeleteShorthandCode(ShorthandCodeListItem? item)
+    {
+        if (item is null) return;
+        _shorthandCodes.Delete(item.Id);
+        LoadShorthandCodes();
+    }
+}
+
+public class ShorthandCodeListItem(ShorthandCode c)
+{
+    public Guid   Id    { get; } = c.Id;
+    public string Code  { get; } = c.Code;
+    public string Label { get; } = c.Label;
+}

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

@@ -0,0 +1,79 @@
+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
+{
+    // ── Fächer ────────────────────────────────────────────────────────────────
+
+    [ObservableProperty] private string _newName          = "";
+    [ObservableProperty] private string _newShort         = "";
+    [ObservableProperty] private string _newNameError     = "";
+
+    public ObservableCollection<SubjectListItem> Subjects { get; } = [];
+
+    // ── Fächer: Laden / Hinzufügen / Löschen ─────────────────────────────────
+
+    public void LoadSubjects()
+    {
+        Subjects.Clear();
+        foreach (var s in _subjects.GetAll())
+            Subjects.Add(new SubjectListItem(s));
+    }
+
+    [RelayCommand]
+    private void AddSubject()
+    {
+        if (string.IsNullOrWhiteSpace(NewName)) { NewNameError = "Name erforderlich."; return; }
+        try
+        {
+            _subjects.Save(new Subject { Name = NewName.Trim(), ShortName = NewShort.Trim() });
+        }
+        catch (InvalidOperationException ex)
+        {
+            NewNameError = ex.Message;
+            return;
+        }
+        NewName = ""; NewShort = ""; NewNameError = "";
+        LoadSubjects();
+    }
+
+    [RelayCommand]
+    private void DeleteSubject(SubjectListItem? item)
+    {
+        if (item is null) return;
+        try
+        {
+            _subjects.Delete(item.Id);
+        }
+        catch (InvalidOperationException ex)
+        {
+            NewNameError = ex.Message;
+            return;
+        }
+        NewNameError = "";
+        if (CatalogSubject?.Id == item.Id) CatalogSubject = null;
+        LoadSubjects();
+    }
+}
+
+public class SubjectListItem(Subject s)
+{
+    public Guid   Id        { get; } = s.Id;
+    public string Name      { get; } = s.Name;
+    public string ShortName { get; } = s.ShortName;
+}

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

@@ -0,0 +1,94 @@
+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
+{
+    // ── Aufsichten: wiederkehrende Pausenaufsicht (4.3 Nachtrag) ─────────────
+
+    [ObservableProperty] private string _newDutyWeekdayName = WeekdayDisplay.Options[0];
+    [ObservableProperty] private int _newDutyAfterPeriod;
+    [ObservableProperty] private string _newDutyLocation = "";
+    [ObservableProperty] private string _newDutyError = "";
+
+    public string[] WeekdayOptions { get; } = WeekdayDisplay.Options;
+    public ObservableCollection<SupervisionDutyItem> SupervisionDuties { get; } = [];
+
+    // ── Aufsichten: Laden / Hinzufügen / Löschen ─────────────────────────────
+
+    private void LoadSupervisionDuties()
+    {
+        SupervisionDuties.Clear();
+        foreach (var d in _supervisionDuties.GetAll())
+            SupervisionDuties.Add(new SupervisionDutyItem(d));
+    }
+
+    [RelayCommand]
+    private void AddSupervisionDuty()
+    {
+        NewDutyError = "";
+        if (string.IsNullOrWhiteSpace(NewDutyLocation)) { NewDutyError = "Ort/Bezeichnung erforderlich."; return; }
+        if (NewDutyAfterPeriod is < 0 or > 10) { NewDutyError = "Muss zwischen 0 und 10 liegen."; return; }
+
+        try
+        {
+            _supervisionDuties.Save(new SupervisionDuty
+            {
+                Weekday = WeekdayDisplay.FromLabel(NewDutyWeekdayName),
+                AfterPeriod = NewDutyAfterPeriod,
+                Location = NewDutyLocation.Trim(),
+            });
+        }
+        catch (InvalidOperationException ex) { NewDutyError = ex.Message; return; }
+
+        NewDutyLocation = ""; NewDutyAfterPeriod = 0;
+        LoadSupervisionDuties();
+    }
+
+    [RelayCommand]
+    private void RemoveSupervisionDuty(SupervisionDutyItem? item)
+    {
+        if (item is null) return;
+        _supervisionDuties.Delete(item.Id);
+        SupervisionDuties.Remove(item);
+    }
+}
+
+public class SupervisionDutyItem(SupervisionDuty d)
+{
+    public Guid   Id           { get; } = d.Id;
+    public string WeekdayLabel { get; } = WeekdayDisplay.Label(d.Weekday);
+    public int    AfterPeriod  { get; } = d.AfterPeriod;
+    public string PeriodLabel  { get; } = d.AfterPeriod == 0 ? "Vor der 1. Stunde" : $"Nach der {d.AfterPeriod}. Stunde";
+    public string Location     { get; } = d.Location;
+}
+
+// ── Wochentag: deutsche Anzeige (Mo–Fr, für Aufsichten) ────────────────────────
+
+public static class WeekdayDisplay
+{
+    private static readonly (DayOfWeek Day, string Name)[] Entries =
+    [
+        (DayOfWeek.Monday, "Montag"), (DayOfWeek.Tuesday, "Dienstag"), (DayOfWeek.Wednesday, "Mittwoch"),
+        (DayOfWeek.Thursday, "Donnerstag"), (DayOfWeek.Friday, "Freitag"),
+    ];
+
+    public static string[] Options { get; } = Entries.Select(e => e.Name).ToArray();
+    public static string Label(DayOfWeek d) => Entries.First(e => e.Day == d).Name;
+    public static DayOfWeek FromLabel(string label) => Entries.FirstOrDefault(e => e.Name == label).Day;
+}
+

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

@@ -0,0 +1,245 @@
+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
+{
+    // ── Synchronisation (Kapitel 10) ──────────────────────────────────────────
+
+    [ObservableProperty] private string _syncServerUrl = "";
+    [ObservableProperty] private string _syncUsername = "";
+    [ObservableProperty] private string _syncPassword = "";
+    [ObservableProperty] private string _syncLoginError = "";
+    [ObservableProperty] private bool   _syncIsLoggedIn;
+    [ObservableProperty] private string _syncConnectionStatus = "";
+    [ObservableProperty] private string _syncForceResyncStatus = "";
+    [ObservableProperty] private bool   _syncForceResyncBusy;
+    [ObservableProperty] private bool   _syncKeyWasRegenerated;
+    [ObservableProperty] private string _recoveryCode = "";
+    [ObservableProperty] private string _recoveryCodeInput = "";
+    [ObservableProperty] private string _recoveryStatus = "";
+    [ObservableProperty] private bool   _recoveryBusy;
+
+    /// Vom Code-Behind gesetzt: lässt den Nutzer die Wiederherstellungsdatei selbst speichern
+    /// (z.B. USB-Stick, eigene Cloud). Liefert false bei Abbruch.
+    public Func<string, Task<bool>>? OnSaveRecoveryFile { get; set; }
+    /// Vom Code-Behind gesetzt: lässt den Nutzer eine zuvor gesicherte Wiederherstellungsdatei
+    /// auswählen. Liefert null bei Abbruch.
+    public Func<Task<string?>>? OnPickRecoveryFile { get; set; }
+    /// Vom Code-Behind gesetzt: bestätigt vor dem Überschreiben des aktuellen Sync-Schlüssels
+    /// dieses Geräts (die App startet danach neu, siehe RedeemRecoveryCode).
+    public Func<Task<bool>>? OnConfirmRecoveryRestore { get; set; }
+
+    public ObservableCollection<SyncConflictListItem> SyncConflicts { get; } = [];
+
+    // ── Synchronisation: Laden / Anmelden / Abmelden / Verbindungstest ───────
+    //
+    // Server-URL, Zugangsdaten und Token werden erst nach erfolgreichem Login zusammen
+    // gespeichert (ein Restart deckt beides ab) — SyncEngine/SnapshotService werden nur einmalig
+    // beim Start registriert (siehe AppBootstrapper), es gibt keinen Live-Re-Registrierungspfad.
+
+    private void LoadSyncSettings()
+    {
+        SyncServerUrl = _syncSettings.ServerUrl;
+        SyncUsername = _syncSettings.Username;
+        SyncIsLoggedIn = _syncSettings.IsLoggedIn;
+    }
+
+    [RelayCommand]
+    private async Task SyncTestConnection()
+    {
+        SyncConnectionStatus = "Teste Verbindung…";
+        if (string.IsNullOrWhiteSpace(SyncServerUrl))
+        {
+            SyncConnectionStatus = "Bitte Server-Adresse eingeben.";
+            return;
+        }
+        var result = await _syncAuth.TestConnectionAsync(SyncServerUrl, _syncSettings.GetToken());
+        SyncConnectionStatus = result switch
+        {
+            SyncConnectionTestResult.Ok => "Verbindung erfolgreich.",
+            SyncConnectionTestResult.Unauthorized => "Server erreichbar, aber nicht angemeldet oder Anmeldung abgelaufen.",
+            SyncConnectionTestResult.IncompatibleVersion =>
+                "Diese App-Version ist veraltet oder nicht mehr mit dem Sync-Server kompatibel. " +
+                "Bitte aktualisiere die LehrerApp.",
+            _ => "Server nicht erreichbar. Bitte Adresse und Internetverbindung prüfen.",
+        };
+    }
+
+    [RelayCommand]
+    private async Task SyncLogin()
+    {
+        SyncLoginError = "";
+        var valid = true;
+        if (string.IsNullOrWhiteSpace(SyncServerUrl)) { SyncLoginError = "Server-Adresse erforderlich."; valid = false; }
+        if (string.IsNullOrWhiteSpace(SyncUsername)) { SyncLoginError = "Benutzername erforderlich."; valid = false; }
+        if (string.IsNullOrWhiteSpace(SyncPassword)) { SyncLoginError = "Passwort erforderlich."; valid = false; }
+        if (!valid) return;
+
+        try
+        {
+            var (token, userId) = await _syncAuth.LoginAsync(SyncServerUrl, SyncUsername, SyncPassword);
+            // Kontowechsel-Erkennung anhand der KANONISCHEN userId aus der Server-Antwort, nicht
+            // anhand von SyncUsername: LiteDBs case-insensitive Standard-Collation lässt einen
+            // Login mit abweichender Groß-/Kleinschreibung erfolgreich durch (TODO 10.2.5), meldet
+            // serverseitig aber trotzdem eine ANDERE userId zurück - die lokale Versionsverfolgung
+            // (BasedOnServerSeq je Entität, Pull-Cursor) bezieht sich dann auf ein fremdes Konto
+            // und muss verworfen werden, sonst lehnt der Server jeden weiteren Push mit einem
+            // dauerhaften 404 beim Nachladen ab (siehe TODO 10.3.5).
+            var accountChanged = _syncSettings.LastUserId is not null && _syncSettings.LastUserId != userId;
+            _syncSettings.SetServerUrl(SyncServerUrl);
+            _syncSettings.SetCredentialsAndToken(SyncUsername, token, userId);
+            if (accountChanged)
+            {
+                _eventQueue.SetLastServerSeq(0);
+                _eventQueue.ResetKnownServerSeqs();
+            }
+            SyncPassword = "";
+            AppBootstrapper.RestartApplication();
+        }
+        catch (SyncAuthException ex) { SyncLoginError = ex.Message; }
+    }
+
+    [RelayCommand]
+    private void SyncLogout()
+    {
+        _syncSettings.Logout();
+        AppBootstrapper.RestartApplication();
+    }
+
+    /// <summary>
+    /// Setzt den lokalen Sync-Fortschritt (Pull-Cursor UND die per-Entität-Versionsverfolgung für
+    /// Push) vollständig zurück und lädt danach alle Ereignisse dieses Nutzers erneut vom Server -
+    /// manueller Reparaturweg, falls dieses Gerät wiederholt keine Änderungen eines anderen Geräts
+    /// erhält (z.B. nach einem lokal bereits zu weit vorgerückten Cursor, TODO 10.1.10) oder eigene
+    /// Pushes dauerhaft mit 404 abgelehnt werden (z.B. nach einem Kontowechsel, TODO 10.3.5).
+    /// Sicher wiederholbar: EventApplier wendet jedes Ereignis über Upsert/Delete-by-Id idempotent
+    /// an, und ein Push ohne bekannten Vorstand wird vom Server als Neuanlage behandelt.
+    /// </summary>
+    [RelayCommand]
+    private async Task SyncForceFullResync()
+    {
+        if (_syncEngine is null) { SyncForceResyncStatus = "Sync nicht konfiguriert."; return; }
+        SyncForceResyncBusy = true;
+        SyncForceResyncStatus = "Lade alle Ereignisse erneut…";
+        try
+        {
+            _eventQueue.SetLastServerSeq(0);
+            _eventQueue.ResetKnownServerSeqs();
+            var result = await _syncEngine.SyncNowAsync();
+            SyncForceResyncStatus = result.Success
+                ? $"Abgeschlossen - {result.EventsPulled} Ereignis(se) erneut geladen."
+                : $"Fehlgeschlagen: {result.Reason}";
+            LoadSyncConflicts();
+        }
+        finally { SyncForceResyncBusy = false; }
+    }
+
+    // ── Sync-Schlüssel: selbstverwalteter Wiederherstellungscode (10.3.2) ────────────────────
+    //
+    // Der Sync-Schlüssel verlässt nie den Server im Klartext (siehe SyncCrypto) - eine echte
+    // Wiederherstellung nach Verlust des einzigen Geräts mit dem Schlüssel ist deshalb nur
+    // möglich, wenn vorher proaktiv ein Rettungsanker angelegt wurde. "Code erzeugen"
+    // verschlüsselt den aktuellen Schlüssel mit einem einmalig angezeigten, zufälligen Code
+    // (SyncCrypto.EncryptKeyWithRecoveryCode) und lässt den Nutzer die verschlüsselte Datei
+    // selbst sichern (USB-Stick, eigene Cloud o.ä.) - Datei und Code getrennt aufbewahren, erst
+    // beides zusammen ergibt den Schlüssel. Läuft komplett offline, ohne Server-Beteiligung.
+
+    [RelayCommand]
+    private async Task CreateRecoveryCode()
+    {
+        if (OnSaveRecoveryFile is null) return;
+        RecoveryBusy = true;
+        RecoveryStatus = "";
+        RecoveryCode = "";
+        try
+        {
+            var code = SyncCrypto.GenerateRecoveryCode();
+            var fileContent = _syncKeyRecovery.CreateRecoveryFile(code);
+            if (!await OnSaveRecoveryFile(fileContent)) { RecoveryStatus = "Abgebrochen."; return; }
+            RecoveryCode = code;
+            RecoveryStatus = "Datei gespeichert. Den Code getrennt von der Datei notieren und " +
+                              "sicher aufbewahren - er wird nirgends gespeichert und lässt sich " +
+                              "nicht erneut anzeigen.";
+        }
+        finally { RecoveryBusy = false; }
+    }
+
+    [RelayCommand]
+    private async Task RedeemRecoveryCode()
+    {
+        RecoveryStatus = "";
+        if (string.IsNullOrWhiteSpace(RecoveryCodeInput)) { RecoveryStatus = "Bitte Code eingeben."; return; }
+        if (OnPickRecoveryFile is null) return;
+        var fileContent = await OnPickRecoveryFile();
+        if (fileContent is null) return;
+        if (OnConfirmRecoveryRestore is not null && !await OnConfirmRecoveryRestore()) return;
+
+        try
+        {
+            _syncKeyRecovery.RestoreFromFile(fileContent, RecoveryCodeInput.Trim());
+        }
+        catch (Exception ex) when (ex is CryptographicException or InvalidOperationException or JsonException)
+        {
+            RecoveryStatus = "Fehlgeschlagen: Code und Datei passen nicht zusammen.";
+            _logger.Error("Sync-Schlüssel-Wiederherstellung fehlgeschlagen", ex);
+            return;
+        }
+        // Der neue Schlüssel liegt jetzt auf der Platte, aber der aktuell im Speicher gehaltene
+        // (falsche) Schlüssel ist ein DI-Singleton und kann zur Laufzeit nicht getauscht werden -
+        // gleiches Muster wie RedeemPairingCode. Lokale Cursor/Versionsverfolgung zurücksetzen,
+        // falls in der Zwischenzeit (mit dem gerade ersetzten, falschen Schlüssel) bereits etwas
+        // synchronisiert wurde - sicher wiederholbar, siehe SyncForceFullResync.
+        _eventQueue.SetLastServerSeq(0);
+        _eventQueue.ResetKnownServerSeqs();
+        AppBootstrapper.RestartApplication();
+    }
+
+    // ── Synchronisation: Konflikte ────────────────────────────────────────────
+    //
+    // Zeigt, was ConflictResolver bereits entschieden hat (welche Seite gewonnen hat) — kein
+    // Feld-Diff für v1, die Payloads sind clientseitig verschlüsselt und würden hier ohnehin nur
+    // rohes JSON zeigen. Minimal: Entität, Zeitpunkt, Ergebnis, "gesehen"-Aktion.
+
+    private void LoadSyncConflicts()
+    {
+        SyncConflicts.Clear();
+        foreach (var c in _eventQueue.GetUnreviewed().OrderByDescending(c => c.DetectedAt))
+            SyncConflicts.Add(new SyncConflictListItem(c));
+    }
+
+    [RelayCommand]
+    private void MarkConflictReviewed(SyncConflictListItem? item)
+    {
+        if (item is null) return;
+        _eventQueue.MarkReviewed(item.Id);
+        SyncConflicts.Remove(item);
+    }
+}
+
+public class SyncConflictListItem(ConflictEntry c)
+{
+    public Guid Id { get; } = c.Id;
+    public string EntityDisplay { get; } = $"{c.RemoteEvent.EntityType} ({c.RemoteEvent.EntityId[..Math.Min(8, c.RemoteEvent.EntityId.Length)]}…)";
+    public string DetectedAtDisplay { get; } = c.DetectedAt.ToLocalTime().ToString("dd.MM.yyyy HH:mm");
+    public string ResolutionDisplay { get; } = c.Resolution switch
+    {
+        "LocalWon" => "Lokale Änderung übernommen (dieses Gerät)",
+        "RemoteWon" => "Änderung vom anderen Gerät übernommen",
+        _ => c.Resolution,
+    };
+}

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

@@ -0,0 +1,170 @@
+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
+{
+    // ── WebUntis-iCal-Abgleich (Nutzer-Feedback) ──────────────────────────────
+
+    [ObservableProperty] private bool   _untisEnabled;
+    [ObservableProperty] private bool   _untisIsConfigured;
+    [ObservableProperty] private string _untisIcalUrlInput = "";
+    [ObservableProperty] private string _untisUrlError = "";
+    [ObservableProperty] private string _untisStatusDisplay = "";
+    [ObservableProperty] private bool   _untisFetchBusy;
+    [ObservableProperty] private bool   _untisApiIsConfigured;
+    [ObservableProperty] private string _untisSchool = "";
+    [ObservableProperty] private string _untisHost = "";
+    [ObservableProperty] private string _untisUsername = "";
+    [ObservableProperty] private string _untisPassword = "";
+    [ObservableProperty] private string _untisApiStatus = "";
+    [ObservableProperty] private bool   _untisApiBusy;
+    [ObservableProperty] private string? _untisHomeroomClassName;
+    public string UntisHomeroomClassDisplay => UntisHomeroomClassName is { Length: > 0 } name
+        ? $"Ausgewählt: {name}"
+        : "Keine Klasse ausgewählt.";
+    partial void OnUntisHomeroomClassNameChanged(string? value) => OnPropertyChanged(nameof(UntisHomeroomClassDisplay));
+    public Func<Task>? OnReviewUntisMapping { get; set; }
+    /// Vom Code-Behind gesetzt: öffnet den WebUntis-Klassenauswahldialog, liefert null bei Abbruch.
+    public Func<Task<(int UntisId, string Name)?>>? OnPickHomeroomClass { get; set; }
+
+    // ── WebUntis-iCal-Abgleich: Laden / Speichern / Entfernen / Jetzt abrufen ────
+    //
+    // Wie bei Sync deckt ein Neustart das Registrieren von UntisSyncService ab
+    // (AppBootstrapper registriert es nur einmalig beim Start, wenn URL+Enabled vorliegen).
+
+    private void LoadUntisSettings()
+    {
+        UntisEnabled = _untisSettings.Enabled;
+        UntisIsConfigured = _untisSettings.IsConfigured;
+        UntisStatusDisplay = _untisSettings.LastSyncAt is { } at
+            ? $"Letzter Abgleich: {at.ToLocalTime():dd.MM.yyyy HH:mm} — {_untisSettings.LastSyncStatus}"
+            : "Noch kein Abgleich durchgeführt.";
+        UntisApiIsConfigured = _untisSettings.ApiIsConfigured;
+        if (_untisSettings.GetApiCredentials() is { } credentials)
+        {
+            UntisSchool = credentials.School;
+            UntisHost = credentials.Host;
+            UntisUsername = credentials.Username;
+            UntisApiStatus = $"API-Zugang für {credentials.Username} ist lokal verschlüsselt gespeichert.";
+        }
+        UntisHomeroomClassName = _untisSettings.HomeroomClassName;
+    }
+
+    [RelayCommand]
+    private async Task UntisSaveApi()
+    {
+        UntisApiStatus = "";
+        if (_untisIntegration is null)
+        {
+            UntisApiStatus = "Die WebUntis-Integration ist nicht verfügbar.";
+            return;
+        }
+        if (string.IsNullOrWhiteSpace(UntisSchool) || string.IsNullOrWhiteSpace(UntisUsername) ||
+            string.IsNullOrWhiteSpace(UntisPassword))
+        {
+            UntisApiStatus = "Schule, Benutzername und Passwort sind erforderlich.";
+            return;
+        }
+        UntisApiBusy = true;
+        try
+        {
+            var credentials = new WebUntisCredentials(UntisSchool.Trim(), UntisHost.Trim(),
+                UntisUsername.Trim(), UntisPassword);
+            await _untisIntegration.ConnectAsync(credentials);
+            _untisSettings.SetApiCredentials(credentials);
+            UntisPassword = "";
+            UntisApiIsConfigured = true;
+            UntisApiStatus = "Anmeldung erfolgreich. Die WebUntis-Session bleibt bei Nutzung bis zu 10 Minuten offen.";
+        }
+        catch (WebUntisIntegrationException ex) { UntisApiStatus = ex.Message; }
+        finally { UntisApiBusy = false; }
+    }
+
+    [RelayCommand]
+    private async Task UntisRemoveApi()
+    {
+        UntisApiBusy = true;
+        try { if (_untisIntegration is not null) await _untisIntegration.DisconnectAsync(); }
+        catch (WebUntisIntegrationException) { /* lokale Zugangsdaten trotzdem sicher entfernen */ }
+        finally
+        {
+            _untisSettings.ClearApiCredentials();
+            UntisPassword = "";
+            UntisApiIsConfigured = false;
+            UntisApiStatus = "WebUntis-API-Zugang entfernt.";
+            UntisApiBusy = false;
+        }
+    }
+
+    [RelayCommand]
+    private void UntisSaveUrl()
+    {
+        UntisUrlError = "";
+        if (string.IsNullOrWhiteSpace(UntisIcalUrlInput)) { UntisUrlError = "iCal-URL erforderlich."; return; }
+        if (!Uri.TryCreate(UntisIcalUrlInput, UriKind.Absolute, out _)) { UntisUrlError = "Ungültige URL."; return; }
+
+        _untisSettings.SetIcalUrl(UntisIcalUrlInput.Trim());
+        _untisSettings.SetEnabled(true);
+        UntisIcalUrlInput = "";
+        AppBootstrapper.RestartApplication();
+    }
+
+    [RelayCommand]
+    private void UntisRemove()
+    {
+        _untisSettings.ClearIcalUrl();
+        LoadUntisSettings();
+        AppBootstrapper.RestartApplication();
+    }
+
+    [RelayCommand]
+    private async Task UntisFetchNow()
+    {
+        if (_untisSync is null) { UntisStatusDisplay = "Abgleich nicht aktiv — App neu starten."; return; }
+        UntisFetchBusy = true;
+        try
+        {
+            await _untisSync.PollAsync();
+            LoadUntisSettings();
+        }
+        finally { UntisFetchBusy = false; }
+    }
+
+    [RelayCommand]
+    private async Task UntisReviewMapping()
+    {
+        if (OnReviewUntisMapping is not null) await OnReviewUntisMapping();
+    }
+
+    [RelayCommand]
+    private async Task UntisPickHomeroomClass()
+    {
+        if (OnPickHomeroomClass is null) return;
+        var result = await OnPickHomeroomClass();
+        if (result is null) return;
+        _untisSettings.SetHomeroomClass(result.Value.UntisId, result.Value.Name);
+        LoadUntisSettings();
+    }
+
+    [RelayCommand]
+    private void UntisClearHomeroomClass()
+    {
+        _untisSettings.SetHomeroomClass(null, null);
+        LoadUntisSettings();
+    }
+}

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

@@ -0,0 +1,80 @@
+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
+{
+    // ── Gewichtungsschema-Voreinstellungen (2.3.3) ───────────────────────────
+
+    [ObservableProperty] private GradingSchemeEditItem _classScheme = null!;
+    [ObservableProperty] private GradingSchemeEditItem _courseScheme = null!;
+
+    // ── Gewichtungsschema-Voreinstellungen: Laden ────────────────────────────
+
+    private void LoadGradingSchemes()
+    {
+        ClassScheme = new GradingSchemeEditItem(
+            _gradingSchemes.GetDefaultForType(GroupType.Class)
+                ?? new GradingScheme { GroupType = GroupType.Class, ExamsPercent = 50, ParticipationPercent = 40, OtherPercent = 10 },
+            "Klassen", _gradingSchemes, _grading);
+        CourseScheme = new GradingSchemeEditItem(
+            _gradingSchemes.GetDefaultForType(GroupType.Course)
+                ?? new GradingScheme { GroupType = GroupType.Course, ExamsPercent = 60, ParticipationPercent = 30, OtherPercent = 10 },
+            "Kurse", _gradingSchemes, _grading);
+    }
+}
+
+// ── GradingSchemeEditItem (2.3) ────────────────────────────────────────────────
+
+public partial class GradingSchemeEditItem : ObservableObject
+{
+    private readonly GradingScheme _scheme;
+    private readonly IGradingSchemeRepository _repo;
+    private readonly GradingService _grading;
+
+    public string Label { get; }
+
+    [ObservableProperty] private double _examsPercent;
+    [ObservableProperty] private double _participationPercent;
+    [ObservableProperty] private double _otherPercent;
+    [ObservableProperty] private string _validationMessage = "";
+    [ObservableProperty] private string _statusMessage = "";
+
+    public GradingSchemeEditItem(GradingScheme scheme, string label, IGradingSchemeRepository repo, GradingService grading)
+    {
+        _scheme = scheme; _repo = repo; _grading = grading;
+        Label = label;
+        _examsPercent = scheme.ExamsPercent;
+        _participationPercent = scheme.ParticipationPercent;
+        _otherPercent = scheme.OtherPercent;
+    }
+
+    [RelayCommand]
+    private void Save()
+    {
+        _scheme.ExamsPercent = ExamsPercent;
+        _scheme.ParticipationPercent = ParticipationPercent;
+        _scheme.OtherPercent = OtherPercent;
+
+        var error = _grading.ValidateGradingScheme(_scheme);
+        if (error is not null) { ValidationMessage = error; StatusMessage = ""; return; }
+
+        ValidationMessage = "";
+        _repo.Save(_scheme);
+        StatusMessage = "Gespeichert.";
+    }
+}

LehrerApp.Desktop/ViewModels/Students/CreateLetterDialogViewModel.cs

@@ -1,21 +1,23 @@
 using CommunityToolkit.Mvvm.ComponentModel;
 using LehrerApp.Core.Interfaces;
 using LehrerApp.Core.Models;
-using LehrerApp.Core.Services;
+using LehrerApp.Templating;
 using System.Collections.ObjectModel;
-using System.Globalization;
 
 namespace LehrerApp.Desktop.ViewModels.Students;
 
 public partial class CreateLetterDialogViewModel : ObservableObject
 {
     private readonly Student _student;
-    private readonly LetterTemplateService _templates;
+    private readonly TemplateStore _templates;
+    private readonly ITemplateRenderer _renderer;
 
     [ObservableProperty] private LetterTemplateChoice? _selectedTemplate;
     [ObservableProperty] private LetterContactChoice? _selectedContact;
     [ObservableProperty] private LetterGroupChoice? _selectedGroup;
     [ObservableProperty] private DateTimeOffset? _letterDate = DateTimeOffset.Now;
+    [ObservableProperty] private string _letterText = "";
+    [ObservableProperty] private string _teacherName = "";
     [ObservableProperty] private string _generationError = "";
     [ObservableProperty] private bool _canGenerate;
 
@@ -28,155 +30,93 @@ public partial class CreateLetterDialogViewModel : ObservableObject
     public bool HasNoTemplates => Templates.Count == 0;
     public bool HasNoContacts => Contacts.Count == 0;
     public string SuggestedFileName => SanitizeFileName(
-        $"{SelectedTemplate?.Name ?? "Elternbrief"}_{_student.LastName}_{_student.FirstName}.docx");
+        $"{SelectedTemplate?.Name ?? "Elternbrief"}_{_student.LastName}_{_student.FirstName}.pdf");
 
-    public CreateLetterDialogViewModel(Student student, LetterTemplateService templates,
+    public CreateLetterDialogViewModel(Student student, TemplateStore templates, ITemplateRenderer renderer,
         IGroupMembershipRepository memberships, IGroupRepository groups)
     {
-        _student = student;
-        _templates = templates;
-
-        foreach (var template in templates.GetTemplates())
-            Templates.Add(new LetterTemplateChoice(template));
-        foreach (var contact in student.Contacts.Where(c => !c.InvalidSince.HasValue).OrderBy(c => c.Name))
-            Contacts.Add(new LetterContactChoice(contact));
+        _student = student; _templates = templates; _renderer = renderer;
+        foreach (var template in templates.GetTemplates()) Templates.Add(new(template));
+        foreach (var contact in student.Contacts.Where(c => !c.InvalidSince.HasValue).OrderBy(c => c.Name)) Contacts.Add(new(contact));
         foreach (var membership in memberships.GetByStudent(student.Id))
-        {
-            var group = groups.GetById(membership.GroupId);
-            if (group is not null) Groups.Add(new LetterGroupChoice(group));
-        }
-
-        SelectedTemplate = Templates.FirstOrDefault();
-        SelectedContact = Contacts.FirstOrDefault();
-        SelectedGroup = Groups.FirstOrDefault();
+            if (groups.GetById(membership.GroupId) is { } group) Groups.Add(new(group));
+        SelectedTemplate = Templates.FirstOrDefault(); SelectedContact = Contacts.FirstOrDefault(); SelectedGroup = Groups.FirstOrDefault();
         RefreshValidation();
     }
 
-    partial void OnSelectedTemplateChanged(LetterTemplateChoice? value)
-    {
-        OnPropertyChanged(nameof(SuggestedFileName));
-        RefreshValidation();
-    }
+    partial void OnSelectedTemplateChanged(LetterTemplateChoice? value) { OnPropertyChanged(nameof(SuggestedFileName)); RefreshValidation(); }
     partial void OnSelectedContactChanged(LetterContactChoice? value) => RefreshValidation();
     partial void OnSelectedGroupChanged(LetterGroupChoice? value) => RefreshValidation();
     partial void OnLetterDateChanged(DateTimeOffset? value) => RefreshValidation();
+    partial void OnLetterTextChanged(string value) => RefreshValidation();
+    partial void OnTeacherNameChanged(string value) => RefreshValidation();
 
     public bool Generate(string outputPath)
     {
-        RefreshValidation();
-        if (!CanGenerate || SelectedTemplate is null) return false;
-        GenerationError = "";
+        RefreshValidation(); if (!CanGenerate || SelectedTemplate is null) return false;
         try
         {
-            _templates.Generate(_templates.GetTemplatePath(SelectedTemplate.Model), outputPath, BuildValues());
-            return true;
-        }
-        catch (Exception ex) when (ex is IOException or InvalidDataException or UnauthorizedAccessException)
-        {
-            GenerationError = $"Der Brief konnte nicht erzeugt werden: {ex.Message}";
-            return false;
+            var pdf = _renderer.RenderToPdf(_templates.Load(SelectedTemplate.Model), new LetterDataProvider(BuildValues()));
+            var directory = Path.GetDirectoryName(outputPath); if (!string.IsNullOrEmpty(directory)) Directory.CreateDirectory(directory);
+            File.WriteAllBytes(outputPath, pdf); GenerationError = ""; return true;
         }
+        catch (Exception ex) when (ex is IOException or InvalidDataException or UnauthorizedAccessException or TemplateValidationException)
+        { GenerationError = $"Der Brief konnte nicht erzeugt werden: {ex.Message}"; return false; }
     }
 
     private void RefreshValidation()
     {
-        Issues.Clear();
-        GenerationError = "";
-
-        if (SelectedTemplate is null)
-            Issues.Add(new("Bitte zuerst in den Einstellungen eine DOCX-Briefvorlage importieren.", true));
-        if (SelectedContact is null)
-            Issues.Add(new("Für den Schüler ist kein aktueller Kontakt ausgewählt.", true));
-        if (LetterDate is null)
-            Issues.Add(new("Bitte ein Briefdatum auswählen.", true));
-
+        Issues.Clear(); GenerationError = "";
+        if (SelectedTemplate is null) Issues.Add(new("Bitte zuerst in den Einstellungen ein .lavorlage-Paket importieren.", true));
+        if (SelectedContact is null) Issues.Add(new("Für den Schüler ist kein aktueller Kontakt ausgewählt.", true));
+        if (LetterDate is null) Issues.Add(new("Bitte ein Briefdatum auswählen.", true));
         if (SelectedTemplate is not null)
         {
-            var validation = _templates.Validate(SelectedTemplate.Model);
-            foreach (var issue in validation.Issues)
-                Issues.Add(new(issue.Message, issue.Severity is TemplateIssueSeverity.StrongWarning or TemplateIssueSeverity.Error));
-
-            var tags = validation.Tags.ToHashSet(StringComparer.Ordinal);
-            var values = BuildValues();
-            foreach (var tag in tags.Where(t => values.TryGetValue(t, out var value) && string.IsNullOrWhiteSpace(value)))
+            try
             {
-                var message = tag switch
-                {
-                    "Letter.Salutation" => "Beim ausgewählten Kontakt fehlt die Briefanrede.",
-                    "Contact.Address" or "Contact.Street" or "Contact.PostalCode" or "Contact.City" =>
-                        $"Beim ausgewählten Kontakt fehlt der Wert für „{tag}“.",
-                    "Group.Name" or "SchoolYear" => "Die Vorlage verwendet Gruppendaten; bitte eine Lerngruppe auswählen.",
-                    _ => $"Für das Vorlagenfeld „{tag}“ ist kein Wert vorhanden.",
-                };
-                Issues.Add(new(message, true));
+                var loaded = _templates.Load(SelectedTemplate.Model); var values = BuildValues();
+                var validation = new TemplateLoader().Validate(loaded, values.ToDictionary(x => x.Key, x => x.Value.Type));
+                foreach (var issue in validation.Issues) Issues.Add(new(issue.Message, issue.Severity == ValidationSeverity.Error));
+                foreach (var required in loaded.Manifest.Placeholders.Where(x => !x.IsConstant && x.Required
+                             && values.TryGetValue(x.Name, out var value) && IsEmpty(value)))
+                    Issues.Add(new($"Für das Pflichtfeld „{required.Name}“ ist kein Wert vorhanden.", true));
             }
+            catch (Exception ex) when (ex is IOException or InvalidDataException or TemplateValidationException)
+            { Issues.Add(new($"Vorlage ist ungültig: {ex.Message}", true)); }
         }
-
-        CanGenerate = SelectedTemplate is not null && SelectedContact is not null && LetterDate is not null
-                      && Issues.Count == 0;
+        CanGenerate = SelectedTemplate is not null && SelectedContact is not null && LetterDate is not null && Issues.Count == 0;
         OnPropertyChanged(nameof(HasIssues));
     }
 
-    private IReadOnlyDictionary<string, string?> BuildValues()
+    private IReadOnlyDictionary<string, PlaceholderValue> BuildValues()
     {
-        var contact = SelectedContact?.Model;
-        var group = SelectedGroup?.Model;
-        var cityLine = string.Join(" ", new[] { contact?.PostalCode, contact?.City }
-            .Where(v => !string.IsNullOrWhiteSpace(v)));
-        var address = string.Join(Environment.NewLine, new[] { contact?.Street, cityLine }
-            .Where(v => !string.IsNullOrWhiteSpace(v)));
-        var date = LetterDate is null ? null : DateOnly.FromDateTime(LetterDate.Value.LocalDateTime)
-            .ToString("dd.MM.yyyy", CultureInfo.GetCultureInfo("de-DE"));
-
-        return new Dictionary<string, string?>
+        var contact = SelectedContact?.Model; var group = SelectedGroup?.Model;
+        var cityLine = string.Join(" ", new[] { contact?.PostalCode, contact?.City }.Where(x => !string.IsNullOrWhiteSpace(x)));
+        var address = string.Join(Environment.NewLine, new[] { contact?.Name, contact?.Street, cityLine }.Where(x => !string.IsNullOrWhiteSpace(x)));
+        var date = DateOnly.FromDateTime((LetterDate ?? DateTimeOffset.Now).LocalDateTime);
+        return new Dictionary<string, PlaceholderValue>(StringComparer.Ordinal)
         {
-            ["Student.FirstName"] = _student.FirstName,
-            ["Student.LastName"] = _student.LastName,
-            ["Contact.Name"] = contact?.Name,
-            ["Contact.Address"] = address,
-            ["Contact.Street"] = contact?.Street,
-            ["Contact.PostalCode"] = contact?.PostalCode,
-            ["Contact.City"] = contact?.City,
-            ["Letter.Salutation"] = contact?.LetterSalutation,
-            ["Group.Name"] = group?.Name,
-            ["SchoolYear"] = group?.SchoolYear,
-            ["CurrentDate"] = date,
+            ["Datum"] = new DateValue(date), ["CurrentDate"] = new DateValue(date),
+            ["Empfaenger"] = new TextValue(contact?.Name ?? ""), ["Anrede"] = new TextValue(contact?.LetterSalutation ?? ""),
+            ["Brieftext"] = new MultilineValue(LetterText), ["LehrerName"] = new TextValue(TeacherName),
+            ["Student.FirstName"] = new TextValue(_student.FirstName), ["Student.LastName"] = new TextValue(_student.LastName),
+            ["Contact.Name"] = new TextValue(contact?.Name ?? ""), ["Contact.Address"] = new MultilineValue(address),
+            ["Contact.Street"] = new TextValue(contact?.Street ?? ""), ["Contact.PostalCode"] = new TextValue(contact?.PostalCode ?? ""),
+            ["Contact.City"] = new TextValue(contact?.City ?? ""), ["Letter.Salutation"] = new TextValue(contact?.LetterSalutation ?? ""),
+            ["Group.Name"] = new TextValue(group?.Name ?? ""), ["SchoolYear"] = new TextValue(group?.SchoolYear ?? ""),
         };
     }
 
+    private static bool IsEmpty(PlaceholderValue value) => value switch
+    { TextValue x => string.IsNullOrWhiteSpace(x.Value), MultilineValue x => string.IsNullOrWhiteSpace(x.Value), _ => false };
     private static string SanitizeFileName(string value)
-    {
-        foreach (var character in Path.GetInvalidFileNameChars()) value = value.Replace(character, '_');
-        return value;
-    }
-}
-
-public sealed class LetterTemplateChoice
-{
-    public LetterTemplateInfo Model { get; }
-    public string Name => Model.Name;
-    public LetterTemplateChoice(LetterTemplateInfo model) => Model = model;
-}
-
-public sealed class LetterContactChoice
-{
-    public Contact Model { get; }
-    public string Display => string.IsNullOrWhiteSpace(Model.Relation)
-        ? Model.Name
-        : $"{Model.Name} · {Model.Relation}";
-    public LetterContactChoice(Contact model) => Model = model;
-}
-
-public sealed class LetterGroupChoice
-{
-    public LearningGroup Model { get; }
-    public string Display => $"{Model.Name} · {Model.SchoolYear}";
-    public LetterGroupChoice(LearningGroup model) => Model = model;
+    { foreach (var character in Path.GetInvalidFileNameChars()) value = value.Replace(character, '_'); return value; }
 }
 
+internal sealed class LetterDataProvider(IReadOnlyDictionary<string, PlaceholderValue> values) : ITemplateDataProvider
+{ public IReadOnlyDictionary<string, PlaceholderValue> GetValues() => values; }
+public sealed class LetterTemplateChoice(InstalledTemplate model) { public InstalledTemplate Model { get; } = model; public string Name => Model.Name; }
+public sealed class LetterContactChoice(Contact model) { public Contact Model { get; } = model; public string Display => string.IsNullOrWhiteSpace(Model.Relation) ? Model.Name : $"{Model.Name} · {Model.Relation}"; }
+public sealed class LetterGroupChoice(LearningGroup model) { public LearningGroup Model { get; } = model; public string Display => $"{Model.Name} · {Model.SchoolYear}"; }
 public sealed class LetterGenerationIssue(string message, bool isStrong)
-{
-    public string Icon { get; } = isStrong ? "⚠" : "ⓘ";
-    public string Message { get; } = message;
-    public string Color { get; } = isStrong ? "#D97706" : "#6B7280";
-}
+{ public string Icon { get; } = isStrong ? "⚠" : "ⓘ"; public string Message { get; } = message; public string Color { get; } = isStrong ? "#D97706" : "#6B7280"; }

LehrerApp.Desktop/ViewModels/Students/DocumentationViewModels.cs

@@ -17,7 +17,7 @@ public record StudentOption(Guid Id, string Name);
 public static class DocumentationTypeDisplay
 {
     public static string[] Options { get; } =
-        ["Gespräch", "Vorkommnis", "Förderplan", "Fehlzeit", "Elternanruf", "Elternbrief"];
+        ["Gespräch", "Vorkommnis", "Förderplan", "Fehlzeit", "Elternanruf", "Elternbrief", "Planung / Erinnerung"];
 
     public static string Label(DocumentationType t) => t switch
     {
@@ -27,6 +27,7 @@ public static class DocumentationTypeDisplay
         DocumentationType.Absence      => "Fehlzeit",
         DocumentationType.ParentCall   => "Elternanruf",
         DocumentationType.ParentLetter => "Elternbrief",
+        DocumentationType.Planning     => "Planung / Erinnerung",
         _ => "",
     };
 
@@ -37,6 +38,7 @@ public static class DocumentationTypeDisplay
         "Fehlzeit"    => DocumentationType.Absence,
         "Elternanruf" => DocumentationType.ParentCall,
         "Elternbrief" => DocumentationType.ParentLetter,
+        "Planung / Erinnerung" => DocumentationType.Planning,
         _             => DocumentationType.Conversation,
     };
 }
@@ -301,7 +303,7 @@ public partial class DocumentationDialogViewModel : ObservableObject
         LetterSentDateError = ""; LetterResponseDateError = "";
         var valid = true;
 
-        if (CanPickStudent && SelectedStudent is null) { StudentError = "Schüler auswählen."; valid = false; }
+        if (CanPickStudent && SelectedStudent is null) { StudentError = "Bezug auswählen."; valid = false; }
 
         if (string.IsNullOrWhiteSpace(Title)) { TitleError = "Titel erforderlich."; valid = false; }
 

LehrerApp.Desktop/ViewModels/Students/GroupDocumentationQuickViewModel.cs

@@ -0,0 +1,46 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using LehrerApp.Core.Models;
+using System.Globalization;
+
+namespace LehrerApp.Desktop.ViewModels.Students;
+
+public sealed record GroupDocumentationOption(Guid Id, string DisplayName);
+
+/// Kompakte Erfassung einer gruppenweiten Planungsnotiz aus der globalen Befehlspalette.
+public partial class GroupDocumentationQuickViewModel(IEnumerable<GroupDocumentationOption> groups)
+    : ObservableObject
+{
+    public List<GroupDocumentationOption> Groups { get; } = groups.ToList();
+    [ObservableProperty] private GroupDocumentationOption? _selectedGroup;
+    [ObservableProperty] private string _title = "";
+    [ObservableProperty] private string _content = "";
+    [ObservableProperty] private string _dateText = DateOnly.FromDateTime(DateTime.Today).ToString("dd.MM.yyyy");
+    [ObservableProperty] private string _groupError = "";
+    [ObservableProperty] private string _titleError = "";
+    [ObservableProperty] private string _dateError = "";
+
+    public Documentation? Result { get; private set; }
+
+    [RelayCommand]
+    private void Save()
+    {
+        GroupError = TitleError = DateError = "";
+        if (SelectedGroup is null) GroupError = "Lerngruppe auswählen.";
+        if (string.IsNullOrWhiteSpace(Title)) TitleError = "Titel erforderlich.";
+        if (!DateOnly.TryParseExact(DateText, "dd.MM.yyyy", null, DateTimeStyles.None, out var date))
+            DateError = "Format TT.MM.JJJJ.";
+        if (GroupError.Length > 0 || TitleError.Length > 0 || DateError.Length > 0) return;
+
+        Result = new Documentation
+        {
+            StudentId = Guid.Empty,
+            GroupId = SelectedGroup!.Id,
+            Type = DocumentationType.Planning,
+            Date = date,
+            Title = Title.Trim(),
+            Content = Content.Trim(),
+            ExcludeFromWebUntisSync = true,
+        };
+    }
+}

LehrerApp.Desktop/ViewModels/Students/StudentViewModels.cs

@@ -64,9 +64,15 @@ public partial class StudentListViewModel : ObservableObject
     [ObservableProperty] private string _searchText = "";
     [ObservableProperty] private bool _showInactive;
     [ObservableProperty] private StudentListItem? _selectedStudent;
+    [ObservableProperty] private bool _isImporting;
 
     public ObservableCollection<StudentListItem> Students { get; } = [];
     public string CountSummary => $"{Students.Count} Schüler gesamt";
+    public bool HasNoStudents => Students.Count == 0;
+    public bool HasStudents => !HasNoStudents;
+    public string EmptyListMessage => string.IsNullOrWhiteSpace(SearchText)
+        ? ShowInactive ? "Noch keine Schüler vorhanden." : "Noch keine aktiven Schüler vorhanden."
+        : "Keine Schüler passen zur aktuellen Suche.";
 
     public StudentListViewModel(IStudentRepository students, IGroupRepository groups,
         IGroupMembershipRepository memberships)
@@ -105,6 +111,9 @@ public partial class StudentListViewModel : ObservableObject
         }
         foreach (var s in f) Students.Add(new StudentListItem(s));
         OnPropertyChanged(nameof(CountSummary));
+        OnPropertyChanged(nameof(HasNoStudents));
+        OnPropertyChanged(nameof(HasStudents));
+        OnPropertyChanged(nameof(EmptyListMessage));
     }
 
     public Func<Task>? OnAddStudent { get; set; }

LehrerApp.Desktop/Views/ClassTeacher/ClassTeacherOverviewView.axaml

@@ -439,7 +439,7 @@
                     <ItemsControl ItemsSource="{Binding PatternNotices}">
                       <ItemsControl.ItemTemplate>
                         <DataTemplate x:DataType="vm:ClassTeacherPatternNotice">
-                          <Grid ColumnDefinitions="4,*" Margin="0,3">
+                          <Grid ColumnDefinitions="4,*,Auto" Margin="0,3">
                             <Border CornerRadius="2" Margin="0,1,8,1" Classes="statusFill"
                                     Classes.info="{Binding IsInfoStatus}"
                                     Classes.warning="{Binding IsWarningStatus}"
@@ -448,6 +448,11 @@
                               <TextBlock Text="{Binding StudentName}" FontSize="12" FontWeight="SemiBold"/>
                               <TextBlock Text="{Binding Message}" FontSize="11" Opacity="0.62" TextWrapping="Wrap"/>
                             </StackPanel>
+                            <Button Grid.Column="2" Classes="rosterRowAction" Content="+"
+                                    IsVisible="{Binding CanCreateReminder}"
+                                    ToolTip.Tip="Wiedervorlage „Eltern kontaktieren&#8220; anlegen"
+                                    Command="{Binding $parent[ItemsControl].((vm:ClassTeacherOverviewViewModel)DataContext).CreateReminderForPatternNoticeCommand}"
+                                    CommandParameter="{Binding}"/>
                           </Grid>
                         </DataTemplate>
                       </ItemsControl.ItemTemplate>

LehrerApp.Desktop/Views/Dashboard/DashboardView.axaml

@@ -20,17 +20,17 @@
     <StackPanel Spacing="20">
 
       <!-- Begrüßung -->
-      <Grid ColumnDefinitions="*,Auto">
+      <Grid RowDefinitions="Auto,Auto">
         <StackPanel>
           <TextBlock Text="{Binding Greeting}" FontSize="14" Opacity="0.6"/>
           <TextBlock Text="{Binding CurrentDate}" FontSize="24" FontWeight="SemiBold"/>
         </StackPanel>
-        <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="8">
+        <WrapPanel Grid.Row="1" Orientation="Horizontal" ItemSpacing="8" LineSpacing="8" Margin="0,10,0,0">
           <Button Content="Klassenbuch abgleichen…" Click="OnCompareWebUntisDocumentationClick"
                   VerticalAlignment="Center"/>
           <Button Content="Bereiche anpassen" Command="{Binding ToggleDashboardSettingsCommand}"
                   VerticalAlignment="Center"/>
-        </StackPanel>
+        </WrapPanel>
       </Grid>
 
       <!-- Der Tagesfokus beantwortet zuerst die vier Fragen, die beim Öffnen der App zählen:
@@ -72,9 +72,13 @@
                 <StackPanel Orientation="Horizontal" Spacing="6">
                   <CheckBox Content="{Binding Title}" IsChecked="{Binding IsVisible}" VerticalAlignment="Center"/>
                   <Button Content="↑" Padding="6,2"
+                          ToolTip.Tip="Bereich nach oben verschieben"
+                          AutomationProperties.Name="Dashboard-Bereich nach oben verschieben"
                           Command="{Binding $parent[ItemsControl].((vm:DashboardViewModel)DataContext).MoveCardUpCommand}"
                           CommandParameter="{Binding}"/>
                   <Button Content="↓" Padding="6,2"
+                          ToolTip.Tip="Bereich nach unten verschieben"
+                          AutomationProperties.Name="Dashboard-Bereich nach unten verschieben"
                           Command="{Binding $parent[ItemsControl].((vm:DashboardViewModel)DataContext).MoveCardDownCommand}"
                           CommandParameter="{Binding}"/>
                 </StackPanel>
@@ -212,7 +216,7 @@
         <Border Grid.Column="{Binding CalendarCard.Column}" Grid.Row="{Binding CalendarCard.Row}"
                 IsVisible="{Binding CalendarCard.EffectiveIsVisible}" Margin="0,0,8,8"
                 Background="{DynamicResource SystemControlBackgroundAltHighBrush}"
-                CornerRadius="8" Padding="16">
+                CornerRadius="8" Padding="16" HorizontalAlignment="Left" MaxWidth="320">
           <StackPanel Spacing="8">
             <StackPanel.Styles>
               <!-- Basiswerte als Style (nicht lokal), damit die spezifischeren Selektoren
@@ -250,8 +254,10 @@
                          Width="130" Margin="12,0"/>
               <Button Grid.Column="2" Content="Heute" FontSize="11" Padding="8,2"
                       Command="{Binding CalendarTodayCommand}" Margin="0,0,4,0"/>
-              <Button Grid.Column="3" Content="‹" Padding="8,2" Command="{Binding PrevMonthCommand}"/>
-              <Button Grid.Column="4" Content="›" Padding="8,2" Command="{Binding NextMonthCommand}" Margin="4,0,0,0"/>
+              <Button Grid.Column="3" Content="‹" Padding="8,2" Command="{Binding PrevMonthCommand}"
+                      ToolTip.Tip="Vorheriger Monat" AutomationProperties.Name="Vorheriger Monat"/>
+              <Button Grid.Column="4" Content="›" Padding="8,2" Command="{Binding NextMonthCommand}" Margin="4,0,0,0"
+                      ToolTip.Tip="Nächster Monat" AutomationProperties.Name="Nächster Monat"/>
             </Grid>
 
             <ItemsControl ItemsSource="{Binding CalendarWeekdayHeaders}">
@@ -273,6 +279,7 @@
               <ItemsControl.ItemTemplate>
                 <DataTemplate x:DataType="vm:CalendarDayCell">
                   <Button Background="Transparent" BorderThickness="0" Padding="0" Margin="1"
+                          HorizontalAlignment="Center"
                           Command="{Binding $parent[ItemsControl].((vm:DashboardViewModel)DataContext).SelectCalendarDayCommand}"
                           CommandParameter="{Binding}" ToolTip.Tip="{Binding Tooltip}">
                     <Border Classes="daycell" Classes.ownclass="{Binding IsOwnClassDay}"
@@ -413,6 +420,56 @@
           </StackPanel>
         </Border>
 
+        <!-- Klausurwochen (Nutzer-Feedback): eigene Klausurlast über alle Kurse hinweg -->
+        <Border Grid.Column="{Binding ExamLoadCard.Column}" Grid.Row="{Binding ExamLoadCard.Row}"
+                IsVisible="{Binding ExamLoadCard.EffectiveIsVisible}" Margin="0,0,8,8" VerticalAlignment="Top"
+                Background="{DynamicResource SystemControlBackgroundAltHighBrush}"
+                CornerRadius="8" Padding="16">
+          <StackPanel>
+            <TextBlock Text="KLAUSURWOCHEN" FontSize="11" FontWeight="Bold"
+                       Opacity="0.5" Margin="0,0,0,10"/>
+            <ItemsControl ItemsSource="{Binding ExamWeekLoads}">
+              <ItemsControl.ItemTemplate>
+                <DataTemplate DataType="vm:ExamWeekLoadItem">
+                  <Grid ColumnDefinitions="*,Auto" Margin="0,4">
+                    <TextBlock Grid.Column="0" Text="{Binding Label}" FontSize="13"/>
+                    <TextBlock Grid.Column="1" Text="{Binding CountDisplay}" Foreground="#F59E0B"
+                               FontSize="12" VerticalAlignment="Center"/>
+                  </Grid>
+                </DataTemplate>
+              </ItemsControl.ItemTemplate>
+            </ItemsControl>
+            <TextBlock Text="Keine Woche mit auffälliger Klausurhäufung." Classes="emptyhint"
+                       IsVisible="{Binding !ExamWeekLoads.Count}"/>
+          </StackPanel>
+        </Border>
+
+        <!-- Unterrichtszeit nacherfassen (Nutzer-Feedback) -->
+        <Border Grid.Column="{Binding MissingTeachingTimeCard.Column}" Grid.Row="{Binding MissingTeachingTimeCard.Row}"
+                IsVisible="{Binding MissingTeachingTimeCard.EffectiveIsVisible}" Margin="0,0,8,8" VerticalAlignment="Top"
+                Background="{DynamicResource SystemControlBackgroundAltHighBrush}"
+                CornerRadius="8" Padding="16">
+          <StackPanel>
+            <TextBlock Text="UNTERRICHTSZEIT NACHERFASSEN" FontSize="11" FontWeight="Bold"
+                       Opacity="0.5" Margin="0,0,0,10"/>
+            <ItemsControl ItemsSource="{Binding MissingTeachingTimeEntries}">
+              <ItemsControl.ItemTemplate>
+                <DataTemplate DataType="vm:MissingTeachingTimeItem">
+                  <Grid ColumnDefinitions="*,Auto" Margin="0,4">
+                    <TextBlock Grid.Column="0" Text="{Binding DateDisplay}" FontSize="13"
+                               VerticalAlignment="Center"/>
+                    <Button Grid.Column="1" Content="Erfassen" FontSize="12" Padding="10,4"
+                            Command="{Binding $parent[ItemsControl].((vm:DashboardViewModel)DataContext).AddMissingTeachingTimeCommand}"
+                            CommandParameter="{Binding}"/>
+                  </Grid>
+                </DataTemplate>
+              </ItemsControl.ItemTemplate>
+            </ItemsControl>
+            <TextBlock Text="Keine fehlende Unterrichtszeit-Erfassung." Classes="emptyhint"
+                       IsVisible="{Binding !MissingTeachingTimeEntries.Count}"/>
+          </StackPanel>
+        </Border>
+
         <!-- Förderplan-Wiedervorlage (5.3.2) -->
         <Border Grid.Column="{Binding SupportCard.Column}" Grid.Row="{Binding SupportCard.Row}"
                 IsVisible="{Binding SupportCard.EffectiveIsVisible}" Margin="8,0,0,8" VerticalAlignment="Top"
@@ -586,10 +643,10 @@
           <StackPanel>
             <TextBlock Text="MEINE LERNGRUPPEN" FontSize="11" FontWeight="Bold"
                        Opacity="0.5" Margin="0,0,0,10"/>
-            <ItemsControl ItemsSource="{Binding CurrentGroups}">
+            <ItemsControl ItemsSource="{Binding CurrentGroups}" HorizontalAlignment="Stretch">
               <ItemsControl.ItemsPanel>
                 <ItemsPanelTemplate>
-                  <WrapPanel Orientation="Horizontal"/>
+                  <WrapPanel Orientation="Horizontal" ItemSpacing="8" LineSpacing="8"/>
                 </ItemsPanelTemplate>
               </ItemsControl.ItemsPanel>
               <ItemsControl.ItemTemplate>
@@ -597,9 +654,15 @@
                   <Button Command="{Binding $parent[ItemsControl].((vm:DashboardViewModel)DataContext).OpenGroupCommand}"
                           CommandParameter="{Binding}"
                           Background="{DynamicResource SystemAccentColorLight2}"
-                          CornerRadius="6" Padding="12,6" Margin="0,0,8,8">
+                          CornerRadius="6" Padding="12,6" MinWidth="150"
+                          ToolTip.Tip="Kurs öffnen">
                     <StackPanel>
+                      <StackPanel Orientation="Horizontal" Spacing="6">
+                        <Border Width="6" Height="6" CornerRadius="3"
+                                Background="{DynamicResource SystemAccentColor}"
+                                IsVisible="{Binding IsOnSelectedDay}" VerticalAlignment="Center"/>
                         <TextBlock Text="{Binding Name}" FontWeight="SemiBold" FontSize="13"/>
+                      </StackPanel>
                       <TextBlock Text="{Binding Subject}" FontSize="11" Opacity="0.7"
                                  IsVisible="{Binding Subject, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
                     </StackPanel>

LehrerApp.Desktop/Views/Exams/ExamsOverviewView.axaml

@@ -182,8 +182,14 @@
     <!-- Liste aller Klausuren, nach Priorität sortiert (nicht nach Datum) ─────────── -->
     <ScrollViewer Grid.Row="2" Margin="20,0,20,16">
       <StackPanel>
-        <TextBlock Text="{Binding EmptyHint}" Classes="emptyhint" Margin="0,20,0,0"
-                    IsVisible="{Binding EmptyHint, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
+        <StackPanel Margin="0,28,0,0" Spacing="10" HorizontalAlignment="Center"
+                    IsVisible="{Binding HasNoExams}">
+          <TextBlock Text="Noch keine Klausuren im aktuellen Schuljahr." Classes="emptyhint"
+                     FontSize="15" TextAlignment="Center"/>
+          <TextBlock Text="Klausuren werden im jeweiligen Kurs angelegt." FontSize="12" Opacity="0.55"/>
+          <Button Content="Zu den Lerngruppen" Command="{Binding GoToGroupsCommand}"
+                  HorizontalAlignment="Center"/>
+        </StackPanel>
         <ItemsControl ItemsSource="{Binding Rows}">
           <ItemsControl.ItemTemplate>
             <DataTemplate x:DataType="vm:ExamListRowViewModel">

LehrerApp.Desktop/Views/Groups/ExamDialog.axaml

@@ -36,6 +36,8 @@
             <TextBox Text="{Binding DateText}" PlaceholderText="TT.MM.JJJJ"/>
             <TextBlock Text="{Binding DateTextError}" Foreground="Red" FontSize="11"
                        IsVisible="{Binding DateTextError, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
+            <TextBlock Text="{Binding WeekLoadHint}" Foreground="#F59E0B" FontSize="11"
+                       IsVisible="{Binding WeekLoadHint, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
           </StackPanel>
           <StackPanel Grid.Column="2" Spacing="4">
             <TextBlock Text="Klausurnummer" FontSize="12" Opacity="0.7"/>

LehrerApp.Desktop/Views/Groups/ExamGradingDialog.axaml.cs

@@ -48,7 +48,7 @@ public partial class ExamGradingDialog : Window
             {
                 Header       = string.IsNullOrWhiteSpace(task.Title) ? $"Aufg. {task.Nr}" : $"{task.Nr}. {task.Title}",
                 Width        = new DataGridLength(1, DataGridLengthUnitType.Star),
-                CellTemplate = BuildPointsCellTemplate(i, grid),
+                CellTemplate = BuildPointsCellTemplate(i, grid, vm.Tasks.Count),
             });
         }
 
@@ -74,7 +74,7 @@ public partial class ExamGradingDialog : Window
         });
     }
 
-    private IDataTemplate BuildPointsCellTemplate(int taskIndex, DataGrid grid)
+    private IDataTemplate BuildPointsCellTemplate(int taskIndex, DataGrid grid, int taskCount)
     {
         var cellName = $"Pts_{taskIndex}";
         return new FuncDataTemplate<ExamResultRow>((row, _) =>
@@ -102,7 +102,7 @@ public partial class ExamGradingDialog : Window
             };
 
             tb.LostFocus += (_, _) => CommitPointsCell(tb, cell);
-            tb.KeyDown += (_, e) => HandleCellKeyDown(e, grid, row, cellName);
+            tb.KeyDown += (_, e) => HandlePointsCellKeyDown(e, grid, row, taskIndex, taskCount);
 
             return tb;
         });
@@ -150,14 +150,53 @@ public partial class ExamGradingDialog : Window
                 Padding = new Thickness(6, 4),
             };
             tb.LostFocus += (_, _) => row.Comment = tb.Text ?? "";
-            tb.KeyDown += (_, e) => HandleCellKeyDown(e, grid, row, cellName);
+            tb.KeyDown += (_, e) => HandleCommentCellKeyDown(e, grid, row, cellName);
             return tb;
         });
     }
 
-    /// Enter/Pfeil-Hoch/Pfeil-Runter springen zur gleichen Spalte in der Nachbarzeile
-    /// (Tab funktioniert bereits über die normale Fokus-Reihenfolge).
-    private void HandleCellKeyDown(KeyEventArgs e, DataGrid grid, object rowItem, string cellName)
+    /// Zwei Korrektur-Workflows (Nutzer-Feedback): "Arbeit für Arbeit" (ein Schüler komplett,
+    /// dann der nächste) und "Aufgabe für Aufgabe" (eine Aufgabe für alle Schüler, dann die
+    /// nächste) — beide bewusst ohne Moduswechsel über zwei verschiedene Tasten, weil sich beide
+    /// Reihenfolgen ohnehin schon auf die Tabelle abbilden (Zeile vs. Spalte). Enter läuft
+    /// zeilenweise (am Zeilenende zurück zu Aufgabe 1 der nächsten Zeile), Pfeil-hoch/-runter
+    /// spaltenweise (am Spaltenende weiter zur Nachbaraufgabe) — beides bricht am Tabellenende
+    /// einfach ab, kein Rundlauf zurück zum Anfang.
+    private void HandlePointsCellKeyDown(KeyEventArgs e, DataGrid grid, ExamResultRow row, int taskIndex, int taskCount)
+    {
+        if (e.Key is not (Key.Down or Key.Up or Key.Enter)) return;
+        e.Handled = true;
+
+        if (grid.ItemsSource is not IList items) return;
+        var rowIdx = items.IndexOf(row);
+        if (rowIdx < 0) return;
+
+        int targetRowIdx;
+        int targetTaskIndex;
+
+        if (e.Key == Key.Enter)
+        {
+            targetTaskIndex = taskIndex + 1;
+            targetRowIdx = rowIdx;
+            if (targetTaskIndex >= taskCount) { targetTaskIndex = 0; targetRowIdx = rowIdx + 1; }
+        }
+        else
+        {
+            targetTaskIndex = taskIndex;
+            targetRowIdx = e.Key == Key.Up ? rowIdx - 1 : rowIdx + 1;
+            if (targetRowIdx < 0) { targetRowIdx = items.Count - 1; targetTaskIndex = taskIndex - 1; }
+            else if (targetRowIdx >= items.Count) { targetRowIdx = 0; targetTaskIndex = taskIndex + 1; }
+        }
+
+        if (targetTaskIndex < 0 || targetTaskIndex >= taskCount
+            || targetRowIdx < 0 || targetRowIdx >= items.Count) return;
+
+        FocusPointsCell(grid, items[targetRowIdx]!, targetTaskIndex);
+    }
+
+    /// Enter/Pfeil-Hoch/Pfeil-Runter springen im Kommentarfeld zur gleichen Spalte in der
+    /// Nachbarzeile (Tab funktioniert bereits über die normale Fokus-Reihenfolge).
+    private void HandleCommentCellKeyDown(KeyEventArgs e, DataGrid grid, object rowItem, string cellName)
     {
         if (e.Key is not (Key.Down or Key.Up or Key.Enter)) return;
         e.Handled = true;
@@ -181,5 +220,25 @@ public partial class ExamGradingDialog : Window
         }, DispatcherPriority.Loaded);
     }
 
+    /// Spalte 0 ist "Schüler", danach folgen die Aufgaben-Spalten in Reihenfolge — daher der
+    /// Offset von 1 beim Auflösen des Spaltenobjekts für ScrollIntoView (muss auch horizontal
+    /// zur Nachbaraufgabe scrollen, nicht nur vertikal zur Nachbarzeile).
+    private void FocusPointsCell(DataGrid grid, object targetItem, int targetTaskIndex)
+    {
+        var targetColumn = grid.Columns.ElementAtOrDefault(1 + targetTaskIndex);
+        if (targetColumn is null) return;
+        grid.ScrollIntoView(targetItem, targetColumn);
+
+        var cellName = $"Pts_{targetTaskIndex}";
+        Dispatcher.UIThread.Post(() =>
+        {
+            var targetTb = grid.GetVisualDescendants().OfType<TextBox>()
+                .FirstOrDefault(t => t.DataContext == targetItem && t.Name == cellName);
+            if (targetTb is null) return;
+            targetTb.Focus();
+            targetTb.SelectAll();
+        }, DispatcherPriority.Loaded);
+    }
+
     private void OnClose(object? sender, RoutedEventArgs e) => Close();
 }

LehrerApp.Desktop/Views/Groups/GradeOverviewTabView.axaml

@@ -19,6 +19,9 @@
       <Button Content="Noten verwalten" Command="{Binding ManageStudentGradesCommand}" Margin="12,0,0,0"
               IsVisible="{Binding SelectedRow, Converter={x:Static ObjectConverters.IsNotNull}}"
               IsEnabled="{Binding !IsReadOnly}"/>
+      <Button Content="Überblick" Command="{Binding ShowPerformanceOverviewCommand}" Margin="6,0,0,0"
+              IsVisible="{Binding SelectedRow, Converter={x:Static ObjectConverters.IsNotNull}}"
+              ToolTip.Tip="Leistungsüberblick mit Zielnoten-Rechner für diesen Schüler"/>
       <Button Content="＋ Sammelnote" Command="{Binding CollectiveGradeCommand}" IsEnabled="{Binding !IsReadOnly}"/>
       <Button Content="Zeugnisnoten" Command="{Binding ReportGradesCommand}" IsEnabled="{Binding !IsReadOnly}"/>
       <Button Content="Als PDF" Click="OnExportPdfClick" Margin="12,0,0,0"

LehrerApp.Desktop/Views/Groups/GradeOverviewTabView.axaml.cs

@@ -25,6 +25,7 @@ public partial class GradeOverviewTabView : UserControl
             vm.OnManageStudentGrades = ShowStudentGradesDialog;
             vm.OnCollectiveGrade = ShowCollectiveGradeDialog;
             vm.OnReportGrades = ShowReportGradesDialog;
+            vm.OnShowPerformanceOverview = ShowPerformanceOverviewDialog;
             vm.PropertyChanged += (_, pe) =>
             {
                 if (pe.PropertyName == nameof(GradeOverviewTabViewModel.RebuildColumnsSignal))
@@ -79,6 +80,22 @@ public partial class GradeOverviewTabView : UserControl
         if (owner is not null) await dialog.ShowDialog(owner);
     }
 
+    private async Task ShowPerformanceOverviewDialog(GradeOverviewRow row)
+    {
+        var dialogVm = new StudentPerformanceOverviewViewModel(
+            App.Services.GetRequiredService<IGradeRepository>(),
+            App.Services.GetRequiredService<IExamRepository>(),
+            App.Services.GetRequiredService<IExamResultRepository>(),
+            App.Services.GetRequiredService<IGroupMembershipRepository>(),
+            App.Services.GetRequiredService<IGradingSchemeRepository>(),
+            App.Services.GetRequiredService<GradingService>(),
+            _vm!.GroupId, row.StudentId, _vm.GroupType, _vm.GradingSystem, row.Name, _vm.GroupLabel, _vm.SchoolYear);
+
+        var dialog = new StudentPerformanceOverviewDialog { DataContext = dialogVm };
+        var owner = TopLevel.GetTopLevel(this) as Window;
+        if (owner is not null) await dialog.ShowDialog(owner);
+    }
+
     private async void OnExportPdfClick(object? sender, RoutedEventArgs e)
     {
         var topLevel = TopLevel.GetTopLevel(this);

LehrerApp.Desktop/Views/Groups/GroupDetailView.axaml

@@ -13,9 +13,9 @@
     <Border Grid.Row="0" Padding="20,16"
             BorderBrush="{DynamicResource SystemControlForegroundBaseLowBrush}"
             BorderThickness="0,0,0,1">
-      <Grid ColumnDefinitions="*,Auto">
-        <shared:PageHeader Grid.Column="0" Title="{Binding GroupTitle}" Subtitle="{Binding GroupSubtitle}"/>
-        <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="8">
+      <Grid RowDefinitions="Auto,Auto">
+        <shared:PageHeader Title="{Binding GroupTitle}" Subtitle="{Binding GroupSubtitle}"/>
+        <WrapPanel Grid.Row="1" Orientation="Horizontal" ItemSpacing="8" LineSpacing="8" Margin="0,10,0,0">
           <TextBlock VerticalAlignment="Center" Opacity="0.6" FontSize="13">
             <Run Text="{Binding StudentCount}"/>
             <Run Text=" Schüler"/>
@@ -34,7 +34,7 @@
           <Button Content="Austragung zurücknehmen" Command="{Binding ReinstateStudentCommand}"
                   IsVisible="{Binding SelectedStudent.HasExitDate}"/>
           <Button Content="＋ Klausur" Command="{Binding AddExamCommand}" IsEnabled="{Binding IsEditable}"/>
-        </StackPanel>
+        </WrapPanel>
       </Grid>
     </Border>
 

LehrerApp.Desktop/Views/Groups/GroupDocumentationTabView.axaml.cs

@@ -28,8 +28,15 @@ public partial class GroupDocumentationTabView : UserControl
         var owner = TopLevel.GetTopLevel(this) as Window;
         if (owner is null) return null;
 
+        var options = new List<StudentOption> { GroupDocumentationTabViewModel.WholeGroupOption };
+        options.AddRange(studentOptions);
         var vm = new DocumentationDialogViewModel(editing?.StudentId ?? Guid.Empty, editing,
-            App.Services.GetRequiredService<IAttachmentStorage>(), studentOptions, groupId);
+            App.Services.GetRequiredService<IAttachmentStorage>(), options, groupId);
+        if (editing is null)
+        {
+            vm.SelectedStudent = GroupDocumentationTabViewModel.WholeGroupOption;
+            vm.TypeName = DocumentationTypeDisplay.Label(DocumentationType.Planning);
+        }
         var dialog = new DocumentationDialog { DataContext = vm };
         var saved = await dialog.ShowDialog<bool>(owner);
         if (!saved) vm.DiscardUnsavedAttachments();

LehrerApp.Desktop/Views/Groups/GroupListView.axaml

@@ -11,13 +11,14 @@
     <Border Grid.Row="0" Padding="20,16"
             BorderBrush="{DynamicResource SystemControlForegroundBaseLowBrush}"
             BorderThickness="0,0,0,1">
-      <Grid ColumnDefinitions="*,Auto,Auto">
-        <shared:PageHeader Grid.Column="0" Title="Lerngruppen" Subtitle="{Binding ListSummary}"/>
-        <ComboBox Grid.Column="1" ItemsSource="{Binding SchoolYears}"
+      <Grid RowDefinitions="Auto,Auto" ColumnDefinitions="*,Auto,Auto">
+        <shared:PageHeader Grid.ColumnSpan="3" Title="Lerngruppen" Subtitle="{Binding ListSummary}"/>
+        <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding SchoolYears}"
                   SelectedItem="{Binding SelectedSchoolYear}"
-                  Width="100" Margin="0,0,8,0" VerticalAlignment="Center"/>
-        <Button Grid.Column="2" Content="＋ Neue Gruppe"
-                Command="{Binding AddGroupCommand}" VerticalAlignment="Center"/>
+                  Width="110" Margin="0,10,8,0" VerticalAlignment="Center"
+                  AutomationProperties.Name="Schuljahr auswählen"/>
+        <Button Grid.Row="1" Grid.Column="2" Content="＋ Neue Gruppe"
+                Command="{Binding AddGroupCommand}" VerticalAlignment="Center" Margin="0,10,0,0"/>
       </Grid>
     </Border>
 
@@ -76,7 +77,7 @@
                       </StackPanel>
                     </StackPanel>
                   </Button>
-                  <Button Grid.Column="2" Content="⋯" Width="36" Height="32" Margin="0,10,10,0"
+                  <Button Grid.Column="2" Content="⋯" Width="40" Height="40" Margin="0,10,10,0"
                           Padding="0" VerticalAlignment="Top"
                           ToolTip.Tip="Lerngruppe verwalten"
                           AutomationProperties.Name="{Binding ManageAutomationName}">

LehrerApp.Desktop/Views/Groups/GroupOverviewTabView.axaml

@@ -66,6 +66,14 @@
           </StackPanel>
         </Border>
 
+        <!-- Klausurschnitt-Vorjahresvergleich (Nutzer-Feedback) -->
+        <Border Classes="card" IsVisible="{Binding HasYearComparison}">
+          <StackPanel>
+            <TextBlock Text="VORJAHRESVERGLEICH" Classes="cardTitle"/>
+            <TextBlock Text="{Binding YearComparisonLabel}" TextWrapping="Wrap" Classes="cardBody"/>
+          </StackPanel>
+        </Border>
+
         <!-- Mitarbeit -->
         <Border Classes="card">
           <StackPanel>

LehrerApp.Desktop/Views/Groups/MoveLessonDialog.axaml

@@ -4,7 +4,7 @@
         x:Class="LehrerApp.Desktop.Views.Groups.MoveLessonDialog"
         x:DataType="vm:MoveLessonDialogViewModel"
         Title="Stunde verschieben"
-        Width="400" Height="260" MinWidth="360" MinHeight="240"
+        Width="440" Height="430" MinWidth="400" MinHeight="400"
         CanResize="False" WindowStartupLocation="CenterOwner">
 
   <Grid RowDefinitions="*,Auto" Margin="24">
@@ -13,6 +13,8 @@
       <TextBlock FontSize="12" Opacity="0.6">
         <Run Text="Bisheriges Datum: "/>
         <Run Text="{Binding CurrentDateDisplay}"/>
+        <Run Text=" · "/>
+        <Run Text="{Binding CurrentPeriodDisplay}"/>
       </TextBlock>
 
       <StackPanel Spacing="4">
@@ -22,6 +24,24 @@
                    IsVisible="{Binding NewDateTextError, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
       </StackPanel>
 
+      <StackPanel Spacing="4">
+        <TextBlock Text="Neue Stunde" FontSize="12" Opacity="0.7"/>
+        <NumericUpDown Value="{Binding NewPeriod}" Minimum="1" Maximum="20"
+                       FormatString="0" PlaceholderText="Stundennummer"/>
+        <TextBlock Text="{Binding NewPeriodError}" Foreground="Red" FontSize="11"
+                   IsVisible="{Binding NewPeriodError, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
+      </StackPanel>
+
+      <Border Background="{DynamicResource SystemControlBackgroundAltHighBrush}" CornerRadius="6"
+              Padding="10" IsVisible="{Binding CanSplitDoubleLesson}">
+        <StackPanel Spacing="5">
+          <CheckBox Content="Nur den zweiten Teil der Doppelstunde verschieben"
+                    IsChecked="{Binding SplitDoubleLesson}"/>
+          <TextBlock Text="Der Verlauf wird an der Dauer der ersten Stunde geteilt. Der zweite Teil wird als eigene Fortsetzungsstunde angelegt."
+                     FontSize="11" Opacity="0.65" TextWrapping="Wrap"/>
+        </StackPanel>
+      </Border>
+
       <CheckBox Content="Folgestunden automatisch verschieben"
                 IsChecked="{Binding ShiftFollowingPlanned}"
                 ToolTip.Tip="Verschiebt alle noch geplanten Stunden derselben Einheit, die nach dieser Stunde liegen, um denselben Zeitraum. Bereits durchgeführte Stunden bleiben unverändert."/>