fix(test): 修复test_agent_docs.py相对路径问题，Unit Tests CI从apps/api运行也能通过 (#989)

apps/worker/video_processing/watermark_engine.py

@@ -14,10 +14,9 @@
 from __future__ import annotations
 
 import logging
-from typing import Any
 
+from packages.domain.watermark_config import WATERMARK_POSITIONS  # noqa: F401
 from packages.domain.watermark_config import (
-    WATERMARK_POSITIONS,
     WatermarkConfig,
 )
 from packages.domain.watermark_config import (  # noqa: F401 — 向后兼容