fix(worker-client): stop swallowing mutating hub call failures

TryInvokeAsync catches every exception and returns null, which is fine
for read-only calls but hid real HubException reasons behind a generic
"offline" message for the 7 mutating call sites (RestoreDefaultAgents,
UpsertPrimeSchedule, AddDailyNote, CleanupFinishedWorktrees,
ResetAllWorktrees, ForceRemoveWorktree, BuildPlanningIntegrationBranch)
— the same bug class fixed for ApproveReview in e1807fd. Each of the 22
TryInvokeAsync call sites was audited; the 15 read-only ones are left
unchanged (empty/offline is the right display). For the 7 switched to
a direct hub invoke, every caller was checked and, where it had no
catch, one was added so the exception surfaces (StatusMessage,
ShowErrorAsync/CombinedWarning) instead of crashing.

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

@@ -24,6 +24,9 @@ public sealed partial class NotesEditorViewModel : ViewModelBase
 
     public NotesEditorViewModel(INotesApi api) => _api = api;
 
+    // Raised when a worker call fails so the host VM can surface it (e.g. via ShowErrorAsync).
+    public event Action<string>? ErrorReported;
+
     public ObservableCollection<NoteBulletViewModel> Bullets { get; } = new();
 
     [ObservableProperty] private DateOnly _currentDay = DateOnly.FromDateTime(DateTime.Today);
@@ -55,9 +58,16 @@ public sealed partial class NotesEditorViewModel : ViewModelBase
     {
         var text = NewBulletText.Trim();
         if (text.Length == 0) return;
-        var dto = await _api.AddAsync(CurrentDay, text);
-        if (dto is not null) Bullets.Add(MakeBullet(dto.Id, dto.Text));
-        NewBulletText = "";
+        try
+        {
+            var dto = await _api.AddAsync(CurrentDay, text);
+            if (dto is not null) Bullets.Add(MakeBullet(dto.Id, dto.Text));
+            NewBulletText = "";
+        }
+        catch (Exception ex)
+        {
+            ErrorReported?.Invoke(ex.Message);
+        }
     }
 
     [RelayCommand] private Task PrevDay() => LoadDayAsync(CurrentDay.AddDays(-1));