fixed all test issues

tests/unit/test_download_models.py

@@ -3,7 +3,7 @@
 This module tests all download-related models including validation,
 serialization, and field constraints.
 """
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 
 import pytest
 from pydantic import ValidationError
@@ -259,14 +259,14 @@ class TestDownloadItem:
     def test_added_at_auto_generated(self):
         """Test that added_at is automatically set."""
         episode = EpisodeIdentifier(season=1, episode=1)
-        before = datetime.utcnow()
+        before = datetime.now(timezone.utc)
         item = DownloadItem(
             id="test_id",
             serie_id="serie_id",
             serie_name="Test",
             episode=episode
         )
-        after = datetime.utcnow()
+        after = datetime.now(timezone.utc)
         assert before <= item.added_at <= after