test(tag): serialize_tag unit tests include the new source/confirmed keys (m139)

The confirm-UI change added source + confirmed to serialize_tag; two exact-dict
unit tests in test_tag_query.py failed on the new keys. Add them (default
None/False for rows without image scope).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CDgx8bQS5YrGRK76v8HUnM

tests/test_tag_query.py

@@ -15,6 +15,8 @@ def test_serialize_tag_with_enum_kind():
     assert serialize_tag(row) == {
         "id": 1, "name": "Sasuke Uchiha", "kind": "character",
         "fandom_id": 5, "fandom_name": "Naruto", "is_system": False,
+        # Applied-tag context defaults for rows without image scope (m139).
+        "source": None, "confirmed": False,
     }
 
 
@@ -27,6 +29,7 @@ def test_serialize_tag_with_string_kind_and_no_fandom():
     assert serialize_tag(row) == {
         "id": 2, "name": "solo", "kind": "general",
         "fandom_id": None, "fandom_name": None, "is_system": False,
+        "source": None, "confirmed": False,
     }