feat(ui): live task updates from worker events + planning polish

Wire TasksIslandViewModel to TaskUpdated/WorktreeUpdated/TaskMessage worker
events so rows refresh without a full reload; add ForegroundHelper to permit
wt.exe to take foreground on planning launch; misc UI polish on lists, task
rows and settings modal.

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

src/ClaudeDo.Ui/ViewModels/Islands/ListNavItemViewModel.cs

@@ -5,8 +5,8 @@ namespace ClaudeDo.Ui.ViewModels.Islands;
 public sealed partial class ListNavItemViewModel : ViewModelBase
 {
     public required string Id { get; init; }
-    public required string Name { get; init; }
     public required ListKind Kind { get; init; }
+    [ObservableProperty] private string _name = "";
     [ObservableProperty] private int _count;
     [ObservableProperty] private bool _isActive;
     [ObservableProperty] private string? _workingDir;