feat: PDF-Druck für Sitzplan, Notenliste, Klausur-Notenspiegel, Kompetenzbericht, Dokumentation

QuestPDF als PDF-Bibliothek eingeführt (11.3), bewusst nur in LehrerApp.Desktop referenziert -
zieht SkiaSharp-Native-Binaries mit, die im Server-Docker-Image nichts verloren haben. Neuer
PdfExportService mit gemeinsamem Kopf-/Fußzeilen-Layout (Titel, Stand-Datum, Seitenzahlen) und
schlanken Druck-DTOs statt ViewModels, damit die Erzeugung ohne Avalonia-Bezug testbar bleibt.
Speicherdialog läuft über den bestehenden ExportService (neues PDF-Format).

Fünf Druckvorlagen (11.4) als "Als PDF"-Button direkt in der jeweiligen Ansicht:
- Sitzplan: Raster mit Tafel-Banner, Tischabständen als echte Lücken, ausgeblendeten Plätzen als
  leere Rasterposition.
- Notenliste: druckt exakt die aktuell angezeigte Matrix (Zeitraum/Darstellung/Sortierung).
- Klausur-Notenspiegel: Kennzahlen, Notenverteilung und Aufgabenanalyse mit Balkendiagrammen,
  auffällig schwache Aufgaben rot markiert.
- Kompetenzbericht: Analyse-Tabelle für den ausgewählten Schüler (erledigt zugleich 8.3.3).
- Schülerdokumentation: alle Einträge chronologisch, vertrauliche/Entwurfs-Einträge markiert.

Layout an gerenderten Muster-PDFs visuell geprüft, nicht nur per Unit-Test.

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

LehrerApp.Desktop/Views/Groups/CompetencyOverviewTabView.axaml

@@ -10,7 +10,10 @@
           <TextBlock Text="Kompetenzübersicht" FontSize="18" FontWeight="SemiBold"/>
           <TextBlock Text="{Binding Summary}" FontSize="12" Opacity="0.65"/>
         </StackPanel>
-        <Button Grid.Column="1" Content="Aktualisieren" Command="{Binding RefreshCommand}"/>
+        <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="8" VerticalAlignment="Top">
+          <Button Content="Als PDF" Click="OnExportPdfClick" IsEnabled="{Binding HasRows}"/>
+          <Button Content="Aktualisieren" Command="{Binding RefreshCommand}"/>
+        </StackPanel>
       </Grid>
 
       <Grid ColumnDefinitions="*,16,210" IsVisible="{Binding HasRows}">

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

@@ -1,8 +1,30 @@
 using Avalonia.Controls;
+using Avalonia.Interactivity;
+using LehrerApp.Desktop.Services;
+using LehrerApp.Desktop.ViewModels.Groups;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace LehrerApp.Desktop.Views.Groups;
 
 public partial class CompetencyOverviewTabView : UserControl
 {
     public CompetencyOverviewTabView() => InitializeComponent();
+
+    private async void OnExportPdfClick(object? sender, RoutedEventArgs e)
+    {
+        var topLevel = TopLevel.GetTopLevel(this);
+        if (topLevel is null || DataContext is not CompetencyOverviewTabViewModel { HasRows: true } vm) return;
+
+        var studentName = vm.SelectedStudent?.DisplayName ?? "Kein Schüler ausgewählt";
+        var data = new CompetencyReportPrintData(vm.GroupLabel, studentName, vm.Summary,
+            vm.ThresholdLabel,
+            vm.Rows.Select(r => new CompetencyReportPrintRow(r.Domain, r.Code, r.Description,
+                r.InstructionCoverage, r.ExamCoverage, r.GroupResult, r.StudentResult,
+                r.Recommendation)).ToList());
+        var pdf = App.Services.GetRequiredService<PdfExportService>().BuildCompetencyReportPdf(data);
+
+        await App.Services.GetRequiredService<ExportService>().SaveAsync(topLevel.StorageProvider,
+            ExportFile.Pdf("Kompetenzbericht als PDF speichern",
+                $"Kompetenzbericht_{vm.GroupLabel}_{studentName}", pdf));
+    }
 }

LehrerApp.Desktop/Views/Groups/ExamEvaluationDialog.axaml

@@ -147,9 +147,10 @@
       </StackPanel>
     </ScrollViewer>
 
-    <Grid Grid.Row="1" ColumnDefinitions="Auto,*,Auto" Margin="0,16,0,0">
+    <Grid Grid.Row="1" ColumnDefinitions="Auto,8,Auto,*,Auto" Margin="0,16,0,0">
       <Button Grid.Column="0" Content="Als CSV exportieren" Click="OnExportClick"/>
-      <Button Grid.Column="2" Content="Fertig" Click="OnClose"/>
+      <Button Grid.Column="2" Content="Als PDF" Click="OnExportPdfClick"/>
+      <Button Grid.Column="4" Content="Fertig" Click="OnClose"/>
     </Grid>
   </Grid>
 </Window>

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

@@ -21,5 +21,33 @@ public partial class ExamEvaluationDialog : Window
         await App.Services.GetRequiredService<ExportService>().SaveAsync(topLevel.StorageProvider, export);
     }
 
+    private async void OnExportPdfClick(object? sender, RoutedEventArgs e)
+    {
+        if (DataContext is not ExamEvaluationDialogViewModel vm) return;
+        var topLevel = TopLevel.GetTopLevel(this);
+        if (topLevel is null) return;
+
+        var stats = new List<LabelValue>
+        {
+            new("Bewertet", vm.GradedCount.ToString()),
+            new("Abwesend", vm.AbsentCount.ToString()),
+            new("Durchschnitt", vm.AverageDisplay),
+            new("Median", vm.MedianDisplay),
+        };
+        if (!string.IsNullOrEmpty(vm.BelowThresholdLabel1))
+            stats.Add(new(vm.BelowThresholdLabel1, vm.BelowThresholdDisplay1));
+        if (!string.IsNullOrEmpty(vm.BelowThresholdLabel2))
+            stats.Add(new(vm.BelowThresholdLabel2, vm.BelowThresholdDisplay2));
+
+        var data = new ExamStatisticsPrintData(vm.ExamTitle, vm.ExamDateLabel, vm.NiveauLabel, stats,
+            vm.GradeDistribution.Select(g => new GradeDistributionPrintRow(g.Grade, g.Count,
+                vm.GradedCount == 0 ? 0 : g.Count * 100.0 / vm.GradedCount)).ToList(),
+            vm.TaskAnalysis.Select(t => new TaskAnalysisPrintRow(t.Label, t.AvgPercent, t.IsWeak)).ToList());
+        var pdf = App.Services.GetRequiredService<PdfExportService>().BuildExamStatisticsPdf(data);
+
+        await App.Services.GetRequiredService<ExportService>().SaveAsync(topLevel.StorageProvider,
+            ExportFile.Pdf("Klausurauswertung als PDF speichern", $"Auswertung_{vm.ExamTitle}", pdf));
+    }
+
     private void OnClose(object? sender, RoutedEventArgs e) => Close();
 }

LehrerApp.Desktop/Views/Groups/GradeOverviewTabView.axaml

@@ -21,6 +21,8 @@
               IsEnabled="{Binding !IsReadOnly}"/>
       <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"
+              IsEnabled="{Binding !!Rows.Count}"/>
     </StackPanel>
 
     <DataGrid Grid.Row="1"

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

@@ -1,7 +1,9 @@
 using Avalonia.Controls;
 using Avalonia.Data;
+using Avalonia.Interactivity;
 using LehrerApp.Core.Interfaces;
 using LehrerApp.Core.Services;
+using LehrerApp.Desktop.Services;
 using LehrerApp.Desktop.ViewModels.Groups;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -77,6 +79,22 @@ public partial class GradeOverviewTabView : UserControl
         if (owner is not null) await dialog.ShowDialog(owner);
     }
 
+    private async void OnExportPdfClick(object? sender, RoutedEventArgs e)
+    {
+        var topLevel = TopLevel.GetTopLevel(this);
+        if (topLevel is null || _vm is null) return;
+
+        var data = new GradeListPrintData(
+            _vm.GroupLabel, _vm.SchoolYear, _vm.SelectedPeriod.Label,
+            _vm.Columns.Select(c => c.Header).ToList(),
+            _vm.Rows.Select(r => new GradeListPrintRow(r.Name, r.Cells, r.TotalDisplay)).ToList());
+        var pdf = App.Services.GetRequiredService<PdfExportService>().BuildGradeListPdf(data);
+
+        await App.Services.GetRequiredService<ExportService>().SaveAsync(topLevel.StorageProvider,
+            ExportFile.Pdf("Notenliste als PDF speichern",
+                $"Notenliste_{_vm.GroupLabel}_{_vm.SchoolYear.Replace('/', '-')}", pdf));
+    }
+
     private void BuildColumns()
     {
         var grid = this.FindControl<DataGrid>("GradesGrid");

LehrerApp.Desktop/Views/Groups/SeatingPlanTabView.axaml

@@ -79,8 +79,11 @@
             </StackPanel>
           </StackPanel>
           <StackPanel Grid.Column="1" VerticalAlignment="Bottom" Spacing="4">
-            <ToggleSwitch Content="Bearbeitungsmodus" IsChecked="{Binding IsEditMode}"
-                          IsVisible="{Binding IsEditable}" HorizontalAlignment="Right"/>
+            <StackPanel Orientation="Horizontal" Spacing="10" HorizontalAlignment="Right">
+              <Button Content="Als PDF" Click="OnExportPdfClick" VerticalAlignment="Center"/>
+              <ToggleSwitch Content="Bearbeitungsmodus" IsChecked="{Binding IsEditMode}"
+                            IsVisible="{Binding IsEditable}"/>
+            </StackPanel>
             <TextBlock Text="{Binding AssignmentSummary}" HorizontalAlignment="Right" FontSize="12" Opacity="0.6"/>
             <TextBlock Text="Ziehen: Platz ändern · Klicken: bewerten" HorizontalAlignment="Right"
                        FontSize="11" Opacity="0.5" IsVisible="{Binding IsEditMode}"/>

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

@@ -5,8 +5,10 @@ using Avalonia.Interactivity;
 using Avalonia.Threading;
 using Avalonia.VisualTree;
 using LehrerApp.Core.Models;
+using LehrerApp.Desktop.Services;
 using LehrerApp.Desktop.ViewModels.Groups;
 using LehrerApp.Desktop.Views.Shared;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace LehrerApp.Desktop.Views.Groups;
 
@@ -205,6 +207,21 @@ public partial class SeatingPlanTabView : UserControl
         await vm.AssessStudent(seat);
     }
 
+    private async void OnExportPdfClick(object? sender, RoutedEventArgs e)
+    {
+        var topLevel = TopLevel.GetTopLevel(this);
+        if (topLevel is null || DataContext is not SeatingPlanTabViewModel { HasSelectedPlan: true } vm) return;
+
+        var data = new SeatingPlanPrintData(
+            vm.PlanTitle, vm.PlanSubtitle, vm.PlanColumns, vm.IsBoardAtBottom, vm.ColumnGapWidths,
+            vm.Seats.Select(s => new SeatPrintCell(s.Row, s.Column,
+                s.IsOccupied ? s.SelectedOption.DisplayName : null, s.IsHidden)).ToList());
+        var pdf = App.Services.GetRequiredService<PdfExportService>().BuildSeatingPlanPdf(data);
+
+        await App.Services.GetRequiredService<ExportService>().SaveAsync(topLevel.StorageProvider,
+            ExportFile.Pdf("Sitzplan als PDF speichern", $"Sitzplan_{vm.PlanTitle}", pdf));
+    }
+
     private async Task ShowAssessmentDialog(SeatAssessmentViewModel vm)
     {
         var dialog = new SeatAssessmentDialog { DataContext = vm };

LehrerApp.Desktop/Views/Students/StudentDetailView.axaml

@@ -245,12 +245,16 @@
               </StackPanel>
             </Border>
 
-            <Grid ColumnDefinitions="*,Auto,Auto">
+            <Grid ColumnDefinitions="*,Auto,Auto,Auto">
               <TextBlock Grid.Column="0" Text="Einträge" FontSize="14" FontWeight="SemiBold" VerticalAlignment="Center"/>
-              <Button Grid.Column="1" Content="Datenauskunft exportieren" FontSize="12" Padding="10,4"
+              <Button Grid.Column="1" Content="Als PDF" FontSize="12" Padding="10,4"
+                      Margin="0,0,8,0" Click="OnExportDocumentationPdfClick"
+                      IsEnabled="{Binding !!Documentation.Count}"
+                      ToolTip.Tip="Alle sichtbaren Dokumentationseinträge dieses Schülers als PDF drucken"/>
+              <Button Grid.Column="2" Content="Datenauskunft exportieren" FontSize="12" Padding="10,4"
                       Margin="0,0,8,0" Command="{Binding ExportPersonalDataCommand}"
                       ToolTip.Tip="Alle gespeicherten Daten dieses Schülers als JSON-Datei exportieren (Art. 15 DSGVO)"/>
-              <Button Grid.Column="2" Content="＋ Eintrag" Command="{Binding AddDocumentationCommand}"/>
+              <Button Grid.Column="3" Content="＋ Eintrag" Command="{Binding AddDocumentationCommand}"/>
             </Grid>
             <TextBlock Text="{Binding ExportStatus}" Foreground="Green" FontSize="12"
                        IsVisible="{Binding ExportStatus, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>

LehrerApp.Desktop/Views/Students/StudentDetailView.axaml.cs

@@ -1,8 +1,10 @@
 using Avalonia.Controls;
 using Avalonia.Input;
+using Avalonia.Interactivity;
 using Avalonia.Platform.Storage;
 using LehrerApp.Core.Interfaces;
 using LehrerApp.Core.Models;
+using LehrerApp.Desktop.Services;
 using LehrerApp.Desktop.ViewModels.Students;
 using LehrerApp.Desktop.Views.Shared;
 using Microsoft.Extensions.DependencyInjection;
@@ -119,6 +121,23 @@ public partial class StudentDetailView : UserControl
         return owner is not null && await dialog.ShowDialog<bool>(owner);
     }
 
+    private async void OnExportDocumentationPdfClick(object? sender, RoutedEventArgs e)
+    {
+        var topLevel = TopLevel.GetTopLevel(this);
+        if (topLevel is null || DataContext is not StudentDetailViewModel { Student: not null } vm
+            || vm.Documentation.Count == 0) return;
+
+        var data = new StudentDocumentationPrintData(vm.Student.FullName,
+            vm.Documentation.Select(d => new DocumentationPrintEntry(
+                d.DateDisplay, d.TypeLabel, d.Model.Title, d.Model.Content,
+                d.Model.Tags, d.IsConfidential, d.IsDraft)).ToList());
+        var pdf = App.Services.GetRequiredService<PdfExportService>().BuildStudentDocumentationPdf(data);
+
+        await App.Services.GetRequiredService<ExportService>().SaveAsync(topLevel.StorageProvider,
+            ExportFile.Pdf("Dokumentation als PDF speichern",
+                $"Dokumentation_{vm.Student.LastName}_{vm.Student.FirstName}", pdf));
+    }
+
     private async Task SaveExportFile(string json)
     {
         var topLevel = TopLevel.GetTopLevel(this);