fix(redis_lock): refactor RedisFairLock to use ZSET for queue management and fix loop shutdown

- Replace list-based queue with sorted set for better dead client cleanup
- Add zombie cleanup buffer to handle expired queue entries
- Fix potential None loop reference in graceful shutdown
- Add task start time to write_message_task result
- Update lock acquisition script to use ZSET operations
- Remove unused queue cleanup scripts
- Ensure proper lock release and renewal failure handling

api/app/tasks.py

@@ -1176,6 +1176,7 @@ def write_message_task(
 
     redis_client = get_sync_redis_client()
     lock = None
+    loop = None
     if redis_client is not None:
         lock = RedisFairLock(
             key=f"memory_write:{end_user_id}",
@@ -1196,6 +1197,7 @@ def write_message_task(
             }
 
     try:
+        task_start_time = int(time.time())
         loop = set_asyncio_event_loop()
 
         result = loop.run_until_complete(_run())
@@ -1219,6 +1221,7 @@ def write_message_task(
         return {
             "status": "SUCCESS",
             "result": result,
+            "start_at": task_start_time,
             "end_user_id": end_user_id,
             "config_id": config_id,
             "elapsed_time": elapsed_time,
@@ -1252,7 +1255,8 @@ def write_message_task(
                 logger.warning(f"[CELERY WRITE] 释放锁失败: {e}")
         # Gracefully shutdown the event loop to prevent
         # 'RuntimeError: Event loop is closed' from httpx.AsyncClient.__del__
-        _shutdown_loop_gracefully(loop)
+        if loop:
+            _shutdown_loop_gracefully(loop)
 
 
 # unused task