fix(ui): stop row buttons flashing disabled while a row command runs

Shared AsyncRelayCommands disabled every row's button during execution.

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

@@ -1173,7 +1173,7 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
         TasksChanged?.Invoke(this, EventArgs.Empty);
     }
 
-    [RelayCommand]
+    [RelayCommand(AllowConcurrentExecutions = true)]
     private async Task ToggleDoneAsync(TaskRowViewModel row)
     {
         if (_worker is null) return;
@@ -1237,7 +1237,7 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
         TasksChanged?.Invoke(this, EventArgs.Empty);
     }
 
-    [RelayCommand]
+    [RelayCommand(AllowConcurrentExecutions = true)]
     private async Task ToggleStarAsync(TaskRowViewModel row)
     {
         row.IsStarred = !row.IsStarred;
@@ -1403,7 +1403,7 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
         catch (Exception ex) { ErrorReported?.Invoke(Loc.T("vm.tasksIsland.sendToQueueFailed", ex.Message)); }
     }
 
-    [RelayCommand]
+    [RelayCommand(AllowConcurrentExecutions = true)]
     private async Task RemoveFromQueueAsync(TaskRowViewModel? row)
     {
         if (row is null || _worker is null) return;
@@ -1700,7 +1700,7 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
         Regroup();
     }
 
-    [RelayCommand]
+    [RelayCommand(AllowConcurrentExecutions = true)]
     private async Task RefineTask(TaskRowViewModel row)
     {
         if (row is null || !row.CanRefine) return;