test(rag): update test for Phase 4 coalescing state

tests/test_rag_engine_ready_status_bug.py

@@ -60,12 +60,17 @@ def test_rag_status_remains_error_after_sync_failure() -> None:
  status to 'ready' - a lie.
  """
  from src.app_controller import AppController
+ import threading
  # Construct a controller, bypassing the full __init__
  ctrl = AppController.__new__(AppController)
  ctrl.rag_config = MagicMock()
  ctrl.rag_config.enabled = True
  ctrl.rag_engine = None
  ctrl.files = []
+ # Phase 4 coalescing state (added by test_infrastructure_hardening_20260609)
+ ctrl._rag_sync_token = 0
+ ctrl._rag_sync_dirty = False
+ ctrl._rag_sync_lock = threading.Lock()
  # Use a mock io_pool to capture the _task function
  submitted_tasks = []
  class MockFuture: