fix(types): resolve pre-existing basedpyright errors in tests

Fix ~790 basedpyright errors across the test suite:
- Type stub subclasses of real production classes with super().__init__()
- Add missing generic type arguments and Dict[str, Any] annotations
- Add None guards before subscript/member access
- Adapt tests to production API changes (removed dead handlers,
  PersistentModelCache.get_default, _i18n_filter_added location)

tests/services/test_model_update_service.py

@@ -391,6 +391,7 @@ async def test_update_in_library_versions_changes_update_state(tmp_path):
     await service.update_in_library_versions("lora", 3, [31, 35])
     record = await service.get_record("lora", 3)
 
+    assert record is not None
     assert record.has_update() is False