feat(ui): move list-settings access from lists pane to tasks header

The gear button on list rows became noisy and overlapped with row
selection. Moves it into the tasks island header where it targets the
currently selected list. Lists pane regains a cleaner row layout.
Also: swallow GetListConfig errors on fresh lists that have no row yet.

src/ClaudeDo.Ui/Services/WorkerClient.cs

@@ -308,7 +308,14 @@ public partial class WorkerClient : ObservableObject, IAsyncDisposable
 
     public async Task<ListConfigDto?> GetListConfigAsync(string listId)
     {
-        return await _hub.InvokeAsync<ListConfigDto?>("GetListConfig", listId);
+        try
+        {
+            return await _hub.InvokeAsync<ListConfigDto?>("GetListConfig", listId);
+        }
+        catch
+        {
+            return null;
+        }
     }
 
     public async Task UpdateTaskAgentSettingsAsync(UpdateTaskAgentSettingsDto dto)