fix: update Subprotocol import and SSL handling in WebSocket modules

- Change Subprotocol import from deprecated websockets.legacy.protocol
  to websockets.typing (canonical location in websockets 13.x)
- Fix SSL context handling in diagnostics.py to properly build
  ssl.SSLContext objects, matching the pattern in manager.py
  (previously passed UNRAID_VERIFY_SSL directly which breaks
  when it's a CA bundle path string)

unraid_mcp/subscriptions/manager.py

@@ -13,7 +13,7 @@ from datetime import datetime
 from typing import Any
 
 import websockets
-from websockets.legacy.protocol import Subprotocol
+from websockets.typing import Subprotocol
 
 from ..config.logging import logger
 from ..config.settings import UNRAID_API_KEY, UNRAID_API_URL, UNRAID_VERIFY_SSL