feat: Enhance Face AI upload functionality and UI

- Updated MainWindow.axaml to increase height and add new UI elements for SSH upload configuration.
- Implemented commands for opening source and destination paths in file explorer.
- Added FaceUploadPath and SSH configuration properties to DataModel and AiSettingsViewModel.
- Introduced validation for FaceUploadPath format and commands for uploading face encoder output.
- Enhanced PickerPreferenceService to manage SSH credentials and upload preferences.
- Updated settings persistence to include FaceUploadPath and SSH preferences.
- Added tests for FaceUploadPath validation and upload command enabling logic.

imagecatalog/Models/SettingsDto.cs

@@ -289,6 +289,10 @@ namespace ImageCatalog_2.Models
         [XmlElement("AI_FaceOutputFolderPath")]
         public string FaceOutputFolderPath { get; set; } = string.Empty;
 
+        [JsonPropertyName("FaceUploadPath")]
+        [XmlElement("AI_FaceUploadPath")]
+        public string FaceUploadPath { get; set; } = string.Empty;
+
         [JsonPropertyName("FaceRecursive")]
         [XmlElement("AI_FaceRecursive")]
         public bool FaceRecursive { get; set; }