fix(ui): wire delete confirm, close-details, uppercase eyebrow, explorer button

- A1: list-name eyebrow runs through UpperCase converter.
- D2: + Open-in-explorer icon button in AgentStrip (Process.Start on worktree path).
- D4: DeleteTaskCommand prompts inline confirm Window before deleting; shell
  wires Details.CloseDetail to clear Tasks.SelectedTask and Details.DeleteFromList
  to reload the current list.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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

@@ -1,5 +1,8 @@
+using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Interactivity;
+using Avalonia.Layout;
+using Avalonia.Media;
 using ClaudeDo.Ui.ViewModels.Islands;
 using ClaudeDo.Ui.Views.Modals;
 
@@ -32,9 +35,56 @@ public partial class DetailsIslandView : UserControl
                 var modal = new WorktreeModalView { DataContext = worktreeVm };
                 await modal.ShowDialog(owner);
             };
+
+            vm.ConfirmAsync = ShowConfirmAsync;
         }
     }
 
+    private async System.Threading.Tasks.Task<bool> ShowConfirmAsync(string message)
+    {
+        var owner = TopLevel.GetTopLevel(this) as Window;
+        if (owner == null) return false;
+
+        var tcs = new TaskCompletionSource<bool>();
+
+        var cancel = new Button { Content = "Cancel", MinWidth = 90 };
+        var confirm = new Button { Content = "Delete", MinWidth = 90, Classes = { "danger" } };
+
+        var dialog = new Window
+        {
+            Title = "Confirm",
+            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 = { cancel, confirm }
+                    }
+                }
+            }
+        };
+
+        cancel.Click += (_, _) => { tcs.TrySetResult(false); dialog.Close(); };
+        confirm.Click += (_, _) => { tcs.TrySetResult(true); dialog.Close(); };
+        dialog.Closed += (_, _) => tcs.TrySetResult(false);
+
+        _ = dialog.ShowDialog(owner);
+        return await tcs.Task;
+    }
+
     private void NotesLostFocus(object? sender, RoutedEventArgs e)
     {
         if (DataContext is DetailsIslandViewModel vm)