K17 fertig.

Erweitert: src/Koogle.Application/Services/CashBookExportService.cs

  PDF-Struktur (QuestPDF 2025.12.1):
  - Header: Titel, Vereinsname, Berichtszeitraum
  - Zusammenfassung: Salden-Tabelle (Anfang/Einnahmen/Ausgaben/End)
  - Kategorien: Einnahmen + Ausgaben mit farbigen Tabellen
  - Footer: Erstelldatum + Seitenzahlen

docs/IMPLEMENTATION_PLAN.md

@@ -1715,7 +1715,7 @@ public enum CashBookEntryType { Income = 0, Expense = 1 }
 | ✓ | K14 | Web | Categories UI | 2 |
 | ✓ | K15 | Web | Reports UI | 2 |
 | ✓ | K16 | Application | Excel Export (ClosedXML) | 3 |
-| ☐ | K17 | Application | PDF Export (QuestPDF) | 1 |
+| ✓ | K17 | Application | PDF Export (QuestPDF) | 1 |
 | ☐ | K18 | Web | Export Controller | 1 |
 | ☐ | K19 | Web | Membership Fees Feature | 2 |
 | ☐ | K20 | Web | Club Settings Extension | 3 |

src/Koogle.Application/Koogle.Application.csproj

@@ -10,6 +10,7 @@
     <PackageReference Include="AutoMapper" Version="15.1.0" />
     <PackageReference Include="ClosedXML" Version="0.105.0" />
     <PackageReference Include="FluentValidation" Version="12.1.1" />
+    <PackageReference Include="QuestPDF" Version="2025.12.1" />
   </ItemGroup>
 
   <ItemGroup>

src/Koogle.Application/Services/CashBookExportService.cs

@@ -2,6 +2,9 @@ using ClosedXML.Excel;
 using Koogle.Application.DTOs;
 using Koogle.Application.Interfaces;
 using Koogle.Domain.Enums;
+using QuestPDF.Fluent;
+using QuestPDF.Helpers;
+using QuestPDF.Infrastructure;
 
 namespace Koogle.Application.Services;
 
@@ -10,6 +13,12 @@ namespace Koogle.Application.Services;
 /// </summary>
 public class CashBookExportService : ICashBookExportService
 {
+    static CashBookExportService()
+    {
+        // QuestPDF Community License
+        QuestPDF.Settings.License = LicenseType.Community;
+    }
+
     /// <inheritdoc />
     public Task<byte[]> ExportToExcelAsync(CashBookReportDto report, string clubName)
     {
@@ -27,8 +36,153 @@ public class CashBookExportService : ICashBookExportService
     /// <inheritdoc />
     public Task<byte[]> ExportToPdfAsync(CashBookReportDto report, string clubName)
     {
-        // Will be implemented in K17 with QuestPDF
+        var document = Document.Create(container =>
-        throw new NotImplementedException("PDF export will be available in a future version.");
+        {
+            container.Page(page =>
+            {
+                page.Size(PageSizes.A4);
+                page.Margin(40);
+                page.DefaultTextStyle(x => x.FontSize(10));
+
+                page.Header().Element(c => ComposeHeader(c, report, clubName));
+                page.Content().Element(c => ComposeContent(c, report));
+                page.Footer().Element(ComposeFooter);
+            });
+        });
+
+        var bytes = document.GeneratePdf();
+        return Task.FromResult(bytes);
+    }
+
+    private static void ComposeHeader(IContainer container, CashBookReportDto report, string clubName)
+    {
+        container.Column(column =>
+        {
+            column.Item().Text("Kassenbericht").FontSize(20).Bold();
+            column.Item().Text(clubName).FontSize(14);
+            column.Item().Text($"Zeitraum: {report.ReportStart:dd.MM.yyyy} - {report.ReportEnd:dd.MM.yyyy}").FontSize(11);
+            column.Item().PaddingBottom(10);
+        });
+    }
+
+    private static void ComposeContent(IContainer container, CashBookReportDto report)
+    {
+        container.Column(column =>
+        {
+            // Summary section
+            column.Item().Text("Zusammenfassung").FontSize(14).Bold();
+            column.Item().PaddingVertical(5).Table(table =>
+            {
+                table.ColumnsDefinition(columns =>
+                {
+                    columns.RelativeColumn(2);
+                    columns.RelativeColumn(1);
+                });
+
+                table.Cell().Text("Anfangssaldo");
+                table.Cell().AlignRight().Text(report.OpeningBalance.ToString("C"));
+
+                table.Cell().Text("Einnahmen");
+                table.Cell().AlignRight().Text($"+{report.TotalIncome:C}").FontColor(Colors.Green.Darken2);
+
+                table.Cell().Text("Ausgaben");
+                table.Cell().AlignRight().Text($"-{report.TotalExpense:C}").FontColor(Colors.Red.Darken2);
+
+                table.Cell().Text("Differenz");
+                table.Cell().AlignRight().Text((report.TotalIncome - report.TotalExpense).ToString("C"));
+
+                table.Cell().Border(1).BorderColor(Colors.Grey.Lighten1).Padding(2).Text("Endsaldo").Bold();
+                table.Cell().Border(1).BorderColor(Colors.Grey.Lighten1).Padding(2).AlignRight().Text(report.ClosingBalance.ToString("C")).Bold();
+            });
+
+            column.Item().PaddingTop(15);
+
+            // Income by category
+            if (report.IncomeByCategory.Count > 0)
+            {
+                column.Item().Text("Einnahmen nach Kategorie").FontSize(12).Bold();
+                column.Item().PaddingVertical(5).Table(table =>
+                {
+                    table.ColumnsDefinition(columns =>
+                    {
+                        columns.RelativeColumn(3);
+                        columns.RelativeColumn(1);
+                        columns.RelativeColumn(1);
+                    });
+
+                    table.Header(header =>
+                    {
+                        header.Cell().Background(Colors.Green.Lighten4).Padding(3).Text("Kategorie").Bold();
+                        header.Cell().Background(Colors.Green.Lighten4).Padding(3).AlignRight().Text("Anzahl").Bold();
+                        header.Cell().Background(Colors.Green.Lighten4).Padding(3).AlignRight().Text("Summe").Bold();
+                    });
+
+                    foreach (var cat in report.IncomeByCategory.OrderByDescending(c => c.Total))
+                    {
+                        table.Cell().Padding(2).Text(cat.CategoryName);
+                        table.Cell().Padding(2).AlignRight().Text(cat.Count.ToString());
+                        table.Cell().Padding(2).AlignRight().Text(cat.Total.ToString("C"));
+                    }
+
+                    table.Cell().Border(1).Padding(2).Text("Gesamt").Bold();
+                    table.Cell().Border(1).Padding(2).AlignRight().Text(report.IncomeByCategory.Sum(c => c.Count).ToString()).Bold();
+                    table.Cell().Border(1).Padding(2).AlignRight().Text(report.TotalIncome.ToString("C")).Bold();
+                });
+            }
+
+            column.Item().PaddingTop(10);
+
+            // Expense by category
+            if (report.ExpenseByCategory.Count > 0)
+            {
+                column.Item().Text("Ausgaben nach Kategorie").FontSize(12).Bold();
+                column.Item().PaddingVertical(5).Table(table =>
+                {
+                    table.ColumnsDefinition(columns =>
+                    {
+                        columns.RelativeColumn(3);
+                        columns.RelativeColumn(1);
+                        columns.RelativeColumn(1);
+                    });
+
+                    table.Header(header =>
+                    {
+                        header.Cell().Background(Colors.Red.Lighten4).Padding(3).Text("Kategorie").Bold();
+                        header.Cell().Background(Colors.Red.Lighten4).Padding(3).AlignRight().Text("Anzahl").Bold();
+                        header.Cell().Background(Colors.Red.Lighten4).Padding(3).AlignRight().Text("Summe").Bold();
+                    });
+
+                    foreach (var cat in report.ExpenseByCategory.OrderByDescending(c => c.Total))
+                    {
+                        table.Cell().Padding(2).Text(cat.CategoryName);
+                        table.Cell().Padding(2).AlignRight().Text(cat.Count.ToString());
+                        table.Cell().Padding(2).AlignRight().Text(cat.Total.ToString("C"));
+                    }
+
+                    table.Cell().Border(1).Padding(2).Text("Gesamt").Bold();
+                    table.Cell().Border(1).Padding(2).AlignRight().Text(report.ExpenseByCategory.Sum(c => c.Count).ToString()).Bold();
+                    table.Cell().Border(1).Padding(2).AlignRight().Text(report.TotalExpense.ToString("C")).Bold();
+                });
+            }
+
+            column.Item().PaddingTop(15);
+
+            // Statistics
+            column.Item().Text($"Anzahl Buchungen: {report.Entries.Count}").FontSize(10);
+        });
+    }
+
+    private static void ComposeFooter(IContainer container)
+    {
+        container.AlignCenter().Text(text =>
+        {
+            text.Span("Erstellt am ");
+            text.Span(DateTime.Now.ToString("dd.MM.yyyy HH:mm"));
+            text.Span(" - Seite ");
+            text.CurrentPageNumber();
+            text.Span(" von ");
+            text.TotalPages();
+        });
     }
 
     private static void CreateSummarySheet(XLWorkbook workbook, CashBookReportDto report, string clubName)