fix: Handle None event_queue in _queue_put, fix test assertion

src/multi_agent_conductor.py

@@ -271,7 +271,8 @@ class ConductorEngine:
 
 def _queue_put(event_queue: events.SyncEventQueue, event_name: str, payload) -> None:
  """Thread-safe helper to push an event to the SyncEventQueue from a worker thread."""
- event_queue.put(event_name, payload)
+ if event_queue is not None:
+  event_queue.put(event_name, payload)
 
 def confirm_execution(payload: str, event_queue: events.SyncEventQueue, ticket_id: str) -> bool:
  """