feat: Krea Image Generation Endpoint

- KreaService: GenerateAsync() mit Job-Polling, Image-Download, Metadaten-Speicherung
- KreaEndpoint: POST /api/images/generate, GET /api/images, GET /api/images/file/{filename}, GET /api/images/status
- KreaImageRecord: Output-Model
- Output: data/images/<timestamp>-<index>.<ext> + data/images/<timestamp>.json
- 16 Modelle: flux, flux-kontext, flux-1.1-pro, imagen-3/4, chatgpt-image, runway-gen-4, etc.
- appsettings.json: KreaToken (Format: KEY_ID:SECRET), obsolete TelegramBotToken/WebhookSecret entfernt

Program.cs

@@ -52,6 +52,11 @@ builder.Services.AddSingleton<TelegramService>(sp =>
         sp.GetRequiredService<AnthropicService>(),
         maxIterations));
 
+// Krea Image Generation
+var kreaToken = builder.Configuration["KreaToken"] ?? "";
+builder.Services.AddSingleton(sp =>
+    new KreaService(sp.GetRequiredService<IHttpClientFactory>(), kreaToken, dataDir));
+
 // Cronjob-Service (BackgroundService)
 builder.Services.AddSingleton<CronjobService>();
 builder.Services.AddHostedService<CronjobService>(sp => sp.GetRequiredService<CronjobService>());
@@ -74,5 +79,6 @@ app.MapProfileEndpoints();
 app.MapSettingsEndpoints();
 app.MapTelegramEndpoints();
 app.MapCronjobEndpoints();
+app.MapKreaEndpoints();
 
 app.Run("http://0.0.0.0:19000");