use new-style query

compendium_v2/auth/session_management.py

+from sqlalchemy import select
 from flask import jsonify
 from datetime import datetime
 from compendium_v2.db import session_scope
@@ -31,7 +32,7 @@ def fetch_user(profile: dict):
 
     with session_scope() as session:
         sub_id = profile['sub']
-        user = session.query(User).filter(User.oidc_sub == sub_id).first()
+        user = session.scalar(select(User).where(User.oidc_sub == sub_id))
         if user is None:
             return None
         user.last_login = datetime.utcnow()
@@ -47,7 +48,7 @@ def user_loader(user_id: str):
     """
 
     with session_scope() as session:
-        user = session.query(User).filter(User.id == user_id).first()
+        user = session.scalar(select(User).where(User.id == user_id))
         if user is None:
             return None
         user.last_login = datetime.utcnow()