K20 fertig. Änderungen:

1. ClubService.cs:134 - MonthlyMembershipFee in UpdateAsync hinzugefügt
  2. Settings.razor:358-364 - Laden der Kassenbuch-Einstellungen beim Init
  3. Settings.razor:665-689 - SaveCashBookSettings() Methode implementiert

  Der Kassenbuch-Tab in den Vereins-Einstellungen funktioniert jetzt:
  - Zeigt aktuellen Kontostand
  - Erlaubt Ändern des monatlichen Mitgliedsbeitrags
  - Speichert Änderungen via Fluxor-Action
  - Quick-Links zu Kassenbuch, Kategorien, Berichten

docs/IMPLEMENTATION_PLAN.md

@@ -1718,7 +1718,7 @@ public enum CashBookEntryType { Income = 0, Expense = 1 }
 | ✓ | K17 | Application | PDF Export (QuestPDF) | 1 |
 | ✓ | K18 | Web | Export Controller | 1 |
 | ✓ | K19 | Web | Membership Fees Feature | 2 |
-| ☐ | K20 | Web | Club Settings Extension | 3 |
+| ✓ | K20 | Web | Club Settings Extension | 3 |
 | ☐ | K21 | Web | Navigation Integration | 1 |
 | ☐ | K22 | Tests | Unit Tests | 2 |
 | ☐ | K23 | Tests | Integration Tests | 1 |

src/Koogle.Application/DTOs/ClubDto.cs

@@ -66,6 +66,11 @@ public record ClubDto
     /// Sender email for club notifications.
     /// </summary>
     public string? SenderEmail { get; init; }
+
+    /// <summary>
+    /// Monthly membership fee amount.
+    /// </summary>
+    public decimal MonthlyMembershipFee { get; init; }
 }
 
 /// <summary>
@@ -123,6 +128,11 @@ public record UpdateClubDto
     /// Sender email for club notifications.
     /// </summary>
     public string? SenderEmail { get; init; }
+
+    /// <summary>
+    /// Monthly membership fee amount.
+    /// </summary>
+    public decimal MonthlyMembershipFee { get; init; }
 }
 
 /// <summary>

src/Koogle.Application/Services/ClubService.cs

@@ -131,6 +131,7 @@ public class ClubService : IClubService
         existing.ExpenseCalculation = dto.ExpenseCalculation;
         existing.ModifiedAt = DateTime.UtcNow;
         existing.SenderEmail = dto.SenderEmail;
+        existing.MonthlyMembershipFee = dto.MonthlyMembershipFee;
 
         var updated = await _clubRepository.UpdateAsync(existing, ct);
         return _mapper.Map<ClubDto>(updated);

src/Koogle.Web/Components/Pages/Settings.razor

@@ -24,6 +24,7 @@
 @inject IState<AuthState> AuthState
 @inject NavigationManager NavigationManager
 @inject IJSRuntime JSRuntime
+@inject ICashBookService CashBookService
 
 <PageTitle>Vereins-Einstellungen</PageTitle>
 
@@ -251,6 +252,58 @@ else
                 </MudCardContent>
             </MudCard>
         </MudTabPanel>
+
+        <MudTabPanel Text="Kassenbuch" Icon="@Icons.Material.Filled.AccountBalance">
+            <MudCard Class="mt-4">
+                <MudCardContent>
+                    <MudText Typo="Typo.h6" Class="mb-4">Kassenbuch-Einstellungen</MudText>
+
+                    <MudGrid>
+                        <MudItem xs="12" sm="6">
+                            <MudNumericField @bind-Value="_monthlyMembershipFee"
+                                Label="Monatlicher Mitgliedsbeitrag"
+                                Format="N2"
+                                Adornment="Adornment.Start"
+                                AdornmentText="€"
+                                Min="0m"
+                                HelperText="Standard-Beitrag für automatische Buchungen" />
+                        </MudItem>
+                        <MudItem xs="12" sm="6">
+                            <MudText Typo="Typo.caption" Color="Color.Secondary" Class="mb-2">Aktueller Kontostand</MudText>
+                            <MudText Typo="Typo.h5" Color="@(_currentBalance >= 0 ? Color.Success : Color.Error)">
+                                @_currentBalance.ToString("C")
+                            </MudText>
+                        </MudItem>
+                    </MudGrid>
+
+                    <MudDivider Class="my-4" />
+
+                    <MudText Typo="Typo.subtitle2" Class="mb-2">Schnellzugriff</MudText>
+                    <MudStack Row="true" Spacing="2">
+                        <MudButton Variant="Variant.Outlined" Color="Color.Primary"
+                                   StartIcon="@Icons.Material.Filled.Book" Href="/cashbook">
+                            Kassenbuch öffnen
+                        </MudButton>
+                        <MudButton Variant="Variant.Outlined" Color="Color.Secondary"
+                                   StartIcon="@Icons.Material.Filled.Category" Href="/cashbook/categories">
+                            Kategorien verwalten
+                        </MudButton>
+                        <MudButton Variant="Variant.Outlined" Color="Color.Info"
+                                   StartIcon="@Icons.Material.Filled.Assessment" Href="/cashbook/reports">
+                            Berichte anzeigen
+                        </MudButton>
+                    </MudStack>
+                </MudCardContent>
+                <MudCardActions>
+                    <MudButton Variant="Variant.Filled" Color="Color.Primary"
+                               StartIcon="@Icons.Material.Filled.Save"
+                               OnClick="SaveCashBookSettings"
+                               Disabled="@(!HasCashBookChanges)">
+                        Speichern
+                    </MudButton>
+                </MudCardActions>
+            </MudCard>
+        </MudTabPanel>
     </MudTabs>
 }
 
@@ -265,6 +318,13 @@ else
     private List<PendingMembershipDto> _pendingMemberships = new();
     private List<UserDto> _clubMembers = new();
 
+    // Cashbook settings
+    private decimal _monthlyMembershipFee;
+    private decimal _originalMembershipFee;
+    private decimal _currentBalance;
+
+    private bool HasCashBookChanges => _monthlyMembershipFee != _originalMembershipFee;
+
     protected override async Task OnInitializedAsync()
     {
         await base.OnInitializedAsync();
@@ -294,6 +354,14 @@ else
 
                 _clubMembers = (await UserService.GetUsersByClubAsync(clubId)).ToList();
                 _isLoadingMembers = false;
+
+                // Load cashbook settings
+                if (_club != null)
+                {
+                    _monthlyMembershipFee = _club.MonthlyMembershipFee;
+                    _originalMembershipFee = _club.MonthlyMembershipFee;
+                    _currentBalance = await CashBookService.GetBalanceAsync();
+                }
             }
         }
         finally
@@ -593,4 +661,30 @@ else
             StateHasChanged();
         }
     }
+
+    private async Task SaveCashBookSettings()
+    {
+        if (_club is null) return;
+
+        try
+        {
+            var dto = new UpdateClubDto
+            {
+                Id = _club.Id,
+                Name = _club.Name,
+                LoginName = _club.LoginName,
+                ExpenseCalculation = _club.ExpenseCalculation,
+                SenderEmail = _club.SenderEmail,
+                MonthlyMembershipFee = _monthlyMembershipFee
+            };
+
+            Dispatcher.Dispatch(new UpdateClubAction(dto));
+            _originalMembershipFee = _monthlyMembershipFee;
+            Snackbar.Add("Kassenbuch-Einstellungen gespeichert", Severity.Success);
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"Fehler: {ex.Message}", Severity.Error);
+        }
+    }
 }