Fix of some timezone problems

Web/modules/database/ausleihung.py

@@ -42,12 +42,12 @@ def _get_client():
     return MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
 # Add this helper function after imports
 def ensure_timezone_aware(dt):
-    """Ensures a datetime is timezone-aware, using UTC if naive"""
+    """Return a timezone-aware datetime, treating naive DB values as UTC."""
     if dt is None:
         return None
     if dt.tzinfo is None:
-        # Treat naive datetimes as UTC
-        return dt.replace(tzinfo=None)
+        # PyMongo returns BSON datetimes as naive UTC unless tz_aware is enabled.
+        return dt.replace(tzinfo=datetime.timezone.utc)
     return dt
 
 def get_current_status(ausleihung, log_changes=False, user=None):
@@ -82,8 +82,8 @@ def get_current_status(ausleihung, log_changes=False, user=None):
         return 'completed'
     
     current_time = datetime.datetime.now(ZoneInfo("Europe/Berlin"))
-    start_time = ausleihung.get('Start')
-    end_time = ausleihung.get('End')
+    start_time = ensure_timezone_aware(ausleihung.get('Start'))
+    end_time = ensure_timezone_aware(ausleihung.get('End'))
     
     # Wenn kein Startdatum vorhanden ist, Status auf 'planned' setzen
     if not start_time: