Refactor application to remove Windows Forms dependencies and transition to Avalonia UI

- Deleted MainWindow.xaml.cs, which contained the WPF implementation of the main window.
- Updated Program.cs to remove Windows Forms initialization and support only Avalonia UI.
- Removed Windows Forms specific code from ViewModelBase, including control marshalling logic.

.vscode/tasks.json

@@ -0,0 +1,18 @@
+{
+  "version": "2.0.0",
+  "tasks": [
+    {
+      "label": "build ImageCatalog Avalonia",
+      "type": "process",
+      "command": "dotnet",
+      "args": [
+        "build",
+        "${workspaceFolder:Catalog}/imagecatalog/ImageCatalog 2.csproj",
+        "--configuration",
+        "Debug"
+      ],
+      "problemMatcher": "$msCompile",
+      "group": "build"
+    }
+  ]
+}