Fix type hints and resource management in coe_mirror

- Add precise type hints: Optional[Tuple[str, str]] for _fetch_creds(),
  List[Tuple[str, str, str]] for notify()
- Wrap requests.Session in context manager for proper cleanup
- Remove unreachable return False after retry loop in _send_matrix()

coe_mirror.py

@@ -17,7 +17,7 @@ import zipfile
 from datetime import datetime, timedelta, timezone
 from pathlib import Path
 from fcntl import flock, LOCK_EX, LOCK_NB
-from typing import Optional
+from typing import List, Optional, Tuple
 from urllib.parse import quote
 
 import requests
@@ -340,7 +340,7 @@ def _write_token_cache(access_token: str, expires_at_iso: str) -> None:
         logger.warning("token cache write failed: %s", exc)
 
 
-def _fetch_creds() -> Optional[tuple]:
+def _fetch_creds() -> Optional[Tuple[str, str]]:
     """Fetch (user, password) from Infisical via creds. Return None on failure."""
     try:
         user = subprocess.run(
@@ -415,7 +415,7 @@ def _send_matrix(message: str) -> bool:
     Non-fatal: any failure logs WARN and returns False. Never raises.
     Implements one 401 retry with token refresh.
     """
-    session = requests.Session()
+    with requests.Session() as session:
         session.headers.update({"User-Agent": USER_AGENT})
 
         encoded_room = quote(MATRIX_ROOM, safe="")
@@ -449,10 +449,9 @@ def _send_matrix(message: str) -> bool:
             except Exception as exc:
                 logger.warning("matrix send unexpected error: %s", exc)
                 return False
-    return False
 
 
-def notify(summary: list) -> None:
+def notify(summary: List[Tuple[str, str, str]]) -> None:
     """Build a Matrix message and POST it. Non-fatal."""
     if not summary:
         return