Improve timezone handling, db models convert naive/timezone-aware

src/ddns_service/cleanup.py

@@ -3,7 +3,7 @@
 import logging
 import threading
 
-from . import utc_now
+from . import now_utc
 from .models import Hostname, User
 from datetime import timedelta
 
@@ -18,7 +18,7 @@ def cleanup_expired(app):
     Returns:
         Number of expired hostnames processed.
     """
-    now = utc_now()
+    now = now_utc()
     expired_count = 0
 
     for hostname in Hostname.select().join(User).where(