Remove stale pylint references and align CI with pre-commit

Remove all pylint inline comments left over after switching to ruff.
Switch CI lint job from bare pip install ruff to pre-commit run,
ensuring CI and pre-commit use the same pinned ruff version.

Signed-off-by: Denys Fedoryshchenko <denys.f@collabora.com>

Author: nuclearcat

api/config.py

@@ -13,6 +13,7 @@ class AuthSettings(BaseSettings):
     """Authentication settings"""
 
     secret_key: str
+    unified_secret: str = ""
     algorithm: str = "HS256"
     # Set to None so tokens don't expire
     access_token_expire_seconds: float = 315360000