fix(app_controller): remove refresh_from_project task that overwrote self.tracks

Root cause: _start_track_logic_result (and _cb_accept_tracks._bg_task)
appended a 'refresh_from_project' task to _pending_gui_tasks at the
end. The main thread processed this task by calling _refresh_from_project,
which does:
    self.tracks = project_manager.get_all_tracks(self.active_project_root)
This REPLACES self.tracks with a fresh disk read. In batched test
environments, the disk read can return 0 tracks (due to timing or
path issues), losing the in-memory tracks that were just appended.

The bg_task already updates self.tracks directly via
self.tracks.append(...). The 'refresh_from_project' task is
unnecessary for the accept flow because the other state
(files, disc_entries, etc.) doesn't change during the accept.

Fix: remove the 'refresh_from_project' task appends from both
_start_track_logic_result and _cb_accept_tracks._bg_task. The
tracks remain in self.tracks after the bg_task completes.

Verified: the failing test combination (test_context_sim_live +
test_mma_concurrent_tracks_execution + test_mma_concurrent_tracks_stress)
now passes 3 consecutive runs (100.57s, 100.29s, 100.18s). The
isolated stress test also still passes (13.92s).

src/app_controller.py

@@ -4674,8 +4674,7 @@ class AppController:
     self.ai_status = f"Processing track {i+1} of {total_tracks}: '{title}'..."
     self._start_track_logic(track_data, skeletons_str=generated_skeletons) # Pass skeletons
    print(f"[DEBUG] _cb_accept_tracks: All {total_tracks} tracks processed.")
-   with self._pending_gui_tasks_lock:
-    self._pending_gui_tasks.append({'action': 'refresh_from_project'}) # Ensure UI refresh after tracks are started
+   # NOTE: Removed the 'refresh_from_project' task append (see _start_track_logic_result).
    self.ai_status = f"All {total_tracks} tracks accepted and execution started."
    return OK
   self.submit_io(_bg_task)
@@ -4802,8 +4801,10 @@ class AppController:
    project_manager.save_track_state(track_id, state, self.active_project_root)
    # Add to memory and notify UI
    self.tracks.append({"id": track_id, "title": title, "status": "todo"})
-   with self._pending_gui_tasks_lock:
-    self._pending_gui_tasks.append({'action': 'refresh_from_project'})
+   # NOTE: Removed the 'refresh_from_project' task append. This task was overwriting
+   # self.tracks with a disk read that could return 0 tracks in batched test environments,
+   # losing the in-memory tracks that were just appended. The tracks are already in
+   # self.tracks; no refresh is needed.
    # 4. Initialize ConductorEngine and run loop
    sys.stderr.write(f"[DEBUG] _start_track_logic: Initializing engine for {track_id}...\n")
    sys.stderr.flush()