feat(worker): report worktree-creation phase on OperationProgress

Fills the silent gap between Queued and the first agent output: WorktreeManager
now broadcasts a "creating_worktree" phase (before the initial git worktree add
and again for the self-heal retry section) through the existing OperationProgress
channel, and the task row shows it via the pre-existing but unused
ops.worker.creatingWorktree locale key until the next entity refresh clears it.

Confirmed the 2026-08-07 triage finding still holds: TaskRunner already
broadcasts WorktreeUpdated right after WorktreeManager.CreateAsync
(TaskRunner.cs:342-346, :501) -- no second broadcast added there.

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

@@ -58,6 +58,12 @@ public sealed partial class TaskRowViewModel : ViewModelBase
     // Set by the custom drag while this row is being dragged — drives the "grabbed" row style.
     [ObservableProperty] private bool _isDragging;
 
+    // Transient: set from HubBroadcaster's OperationProgress while the worker is still creating
+    // this task's worktree (the silent gap between Queued and the first agent output). Cleared
+    // by the next entity refresh — UpdateFromEntity always reflects a settled state, so there's
+    // nothing left to show past that point.
+    [ObservableProperty] private string? _creationPhase;
+
     // True while a drag is hovering this row (i.e. it would show a drop-hint gap). Used to
     // suppress the ordinary hover highlight/transitions so they don't fight the hint.
     public bool IsDropTarget => DropHintAbove || DropHintBelow;
@@ -145,6 +151,16 @@ public sealed partial class TaskRowViewModel : ViewModelBase
         ? "1 roadblock reported during the run — see details"
         : $"{RoadblockCount} roadblocks reported during the run — see details";
 
+    /// Mirrors WorktreeManager.PhaseCreatingWorktree — a hub payload token, not a display string.
+    private const string PhaseCreatingWorktree = "creating_worktree";
+
+    public bool HasCreationPhase => CreationPhase is not null;
+    public string? CreationPhaseLabel => CreationPhase switch
+    {
+        PhaseCreatingWorktree => Loc.T("ops.worker.creatingWorktree"),
+        _ => null,
+    };
+
     // True for every Failed task, even one that predates this field — FailureReasonLabel then
     // falls back to "unknown" instead of leaving the tooltip blank.
     public bool HasFailureReason => Status == TaskStatus.Failed;
@@ -345,6 +361,11 @@ public sealed partial class TaskRowViewModel : ViewModelBase
     partial void OnRoadblockCountChanged(int value) { OnPropertyChanged(nameof(HasRoadblock)); OnPropertyChanged(nameof(RoadblockTooltip)); }
     partial void OnDropHintAboveChanged(bool value) => OnPropertyChanged(nameof(IsDropTarget));
     partial void OnDropHintBelowChanged(bool value) => OnPropertyChanged(nameof(IsDropTarget));
+    partial void OnCreationPhaseChanged(string? value)
+    {
+        OnPropertyChanged(nameof(HasCreationPhase));
+        OnPropertyChanged(nameof(CreationPhaseLabel));
+    }
 
     public void RefreshLocalized()
     {
@@ -363,6 +384,9 @@ public sealed partial class TaskRowViewModel : ViewModelBase
 
     public void UpdateFromEntity(TaskEntity t)
     {
+        // Any entity-backed refresh reflects a settled state, so the transient creation-phase
+        // banner (set from the OperationProgress broadcast) has nothing left to announce.
+        CreationPhase     = null;
         var (add, del) = ParseDiffStat(t.Worktree?.DiffStat);
         Number            = t.Number;
         Title             = t.Title;