feat(ui): hide list chip outside virtual list views

Task rows now expose a ShowListChip flag that the tasks island sets
only for Virtual list kinds, so the chip stops being redundant when
viewing a single concrete list.

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

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

@@ -28,6 +28,7 @@ public sealed partial class TaskRowViewModel : ViewModelBase
     [ObservableProperty] private bool _isExpanded = true;
     [ObservableProperty] private bool _hasPlanningChildren;
     [ObservableProperty] private bool _hasQueuedSubtasks;
+    [ObservableProperty] private bool _showListChip = true;
 
     public DateTime CreatedAt { get; init; }
     public string CreatedAtFormatted => CreatedAt == default ? "—" : $"Created {CreatedAt:MMM d}";