Add manual uploader credentials fields

clients/photobooth-uploader/PhotoboothUploader/MainWindow.axaml

@@ -65,6 +65,14 @@
                     <TextBox x:Name="BaseUrlBox" Watermark="https://fotospiel.app" />
                     <TextBlock Text="Max. parallele Uploads" />
                     <TextBox x:Name="MaxUploadsBox" Watermark="2" />
+                    <TextBlock Text="Manuelle Zugangsdaten (optional)" FontWeight="SemiBold" Margin="0,8,0,0" />
+                    <TextBlock Text="Diese Felder ueberschreiben den Verbindungscode." Classes="subtitle" TextWrapping="Wrap" />
+                    <TextBlock Text="Upload-URL" />
+                    <TextBox x:Name="ManualUploadUrlBox" Watermark="https://fotospiel.app/api/v1/photobooth/upload" />
+                    <TextBlock Text="Benutzername" />
+                    <TextBox x:Name="ManualUsernameBox" />
+                    <TextBlock Text="Passwort" />
+                    <TextBox x:Name="ManualPasswordBox" PasswordChar="•" />
                     <Button x:Name="SaveAdvancedButton" Content="Speichern" Click="SaveAdvancedButton_Click" Classes="primary" />
                 </StackPanel>
             </Border>

clients/photobooth-uploader/PhotoboothUploader/MainWindow.axaml.cs

@@ -171,6 +171,9 @@ public partial class MainWindow : Window
 
         BaseUrlBox.Text = _settings.BaseUrl ?? DefaultBaseUrl;
         MaxUploadsBox.Text = _settings.MaxConcurrentUploads.ToString();
+        ManualUploadUrlBox.Text = _settings.UploadUrl ?? string.Empty;
+        ManualUsernameBox.Text = _settings.Username ?? string.Empty;
+        ManualPasswordBox.Text = string.Empty;
 
         if (!string.IsNullOrWhiteSpace(_settings.UploadUrl))
         {
@@ -423,8 +426,28 @@ public partial class MainWindow : Window
             return;
         }
 
+        var manualUploadUrl = (ManualUploadUrlBox.Text ?? string.Empty).Trim();
+        var manualUsername = (ManualUsernameBox.Text ?? string.Empty).Trim();
+        var manualPassword = (ManualPasswordBox.Text ?? string.Empty).Trim();
+
         _settings.BaseUrl = normalizedBaseUrl;
         _settings.MaxConcurrentUploads = maxUploads;
+
+        if (!string.IsNullOrWhiteSpace(manualUploadUrl))
+        {
+            _settings.UploadUrl = ResolveUploadUrl(manualUploadUrl);
+        }
+
+        if (!string.IsNullOrWhiteSpace(manualUsername))
+        {
+            _settings.Username = manualUsername;
+        }
+
+        if (!string.IsNullOrWhiteSpace(manualPassword))
+        {
+            _settings.Password = manualPassword;
+        }
+
         _settingsStore.Save(_settings);
 
         _client = new PhotoboothConnectClient(_settings.BaseUrl, _userAgent);
@@ -432,6 +455,15 @@ public partial class MainWindow : Window
         UpdateDiagnostics();
         UpdateFolderHealth();
         RestartUploadPipeline();
+        UpdateSteps();
+
+        if (!string.IsNullOrWhiteSpace(_settings.UploadUrl))
+        {
+            StatusText.Text = "Verbunden. Upload bereit.";
+            PickFolderButton.IsEnabled = true;
+            TestUploadButton.IsEnabled = true;
+            ReconnectButton.IsEnabled = true;
+        }
         UpdateStatus("Einstellungen gespeichert.");
     }