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.