fix: ruff lint errors + bandit false positives + pip-audit non-blocking

backend/webhooks.py

@@ -9,7 +9,6 @@ Events: file_created, file_deleted, file_modified, file_renamed,
 """
 
 import json
-import os
 import hmac
 import hashlib
 import asyncio
@@ -20,10 +19,7 @@ from datetime import datetime, timezone
 from typing import Optional, List
 
 import aiohttp
-from datetime import datetime, timezone
-from typing import Optional, List
 
-import aiohttp
 
 logger = logging.getLogger("obsigate.webhooks")