feat(ui): add delete-list button to List Settings modal

src/ClaudeDo.Ui/Views/Islands/ListsIslandView.axaml.cs

@@ -26,6 +26,8 @@ public partial class ListsIslandView : UserControl
                 {
                     var window = new ListSettingsModalView { DataContext = modal };
                     modal.CloseAction = () => window.Close();
+                    modal.ConfirmAsync = ShowConfirmAsync;
+                    modal.ShowErrorAsync = ShowErrorDialogAsync;
                     var top = TopLevel.GetTopLevel(this) as Window;
                     if (top is null) window.Show();
                     else await window.ShowDialog(top);
@@ -93,6 +95,43 @@ public partial class ListsIslandView : UserControl
     private static System.Threading.Tasks.Task JumpToTaskAsync(IslandsShellViewModel s, string listId, string taskId)
         => JumpToTaskHelper.SelectAsync(s, listId, taskId);
 
+    private async System.Threading.Tasks.Task ShowErrorDialogAsync(string message)
+    {
+        var owner = TopLevel.GetTopLevel(this) as Window;
+        if (owner is null) return;
+
+        var ok = new Button { Content = "OK", MinWidth = 90 };
+        var dialog = new Window
+        {
+            Title = "Error",
+            Width = 360,
+            SizeToContent = SizeToContent.Height,
+            CanResize = false,
+            WindowStartupLocation = WindowStartupLocation.CenterOwner,
+            ShowInTaskbar = false,
+            Background = this.FindResource("SurfaceBrush") as IBrush,
+            Content = new StackPanel
+            {
+                Spacing = 16,
+                Margin = new Thickness(20),
+                Children =
+                {
+                    new TextBlock { Text = message, TextWrapping = TextWrapping.Wrap },
+                    new StackPanel
+                    {
+                        Orientation = Orientation.Horizontal,
+                        Spacing = 8,
+                        HorizontalAlignment = HorizontalAlignment.Right,
+                        Children = { ok },
+                    },
+                },
+            },
+        };
+
+        ok.Click += (_, _) => dialog.Close();
+        await dialog.ShowDialog(owner);
+    }
+
     private async System.Threading.Tasks.Task<bool> ShowConfirmAsync(string message)
     {
         var owner = TopLevel.GetTopLevel(this) as Window;