Enhanced logging, diagnostics, and robustness throughout

Added NLog-based logging and diagnostics to Console and WPF apps, with programmatic configuration and support for debugger output. Refactored apps to use dependency injection and Microsoft.Extensions.Hosting. Improved output layer extraction and fallback logic in detection/recognition, including objectness-class probability multiplication. Added crop saving for diagnostics. Introduced new CLI options for diagnostics. MainViewModel and MainWindow now use DI and log errors. NumberRecognitionEngine supports logging, crop saving, and robust fallback. Added Python diagnostic script. Improved error handling and argument parsing.

src/AIFotoONLUS.Core/ModelConfiguration.cs

@@ -16,5 +16,7 @@ namespace AIFotoONLUS.Core
         public Size RecognitionInputSize { get; set; } = new Size(140, 120);
 
         public string[] NumberClasses { get; set; } = new[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
+        // When true, recognition crops will be saved to disk for diagnostics. Disabled by default.
+        public bool EnableCropSaving { get; set; } = false;
     }
 }