feat(ui): complete Avalonia UI port with 7 main pages, tool settings & top MenuBar

src/ClawdDotNet.Desktop/Views/AddAgentWindow.axaml.cs

@@ -0,0 +1,21 @@
+using Avalonia.Controls;
+using ClawdDotNet.Desktop.ViewModels;
+
+namespace ClawdDotNet.Desktop.Views;
+
+public partial class AddAgentWindow : Window
+{
+    public AddAgentWindow()
+    {
+        InitializeComponent();
+    }
+
+    protected override void OnDataContextChanged(EventArgs e)
+    {
+        base.OnDataContextChanged(e);
+        if (DataContext is AddAgentViewModel vm)
+        {
+            vm.CloseRequested += () => Close();
+        }
+    }
+}