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_civitai_image_parser.py

@@ -91,7 +91,7 @@ async def test_parse_metadata_handles_nested_meta_and_lowercase_hashes(monkeypat
         },
     }
 
-    assert parser.is_metadata_matching(metadata)
+    assert parser.is_metadata_matching(metadata)  # pyright: ignore[reportArgumentType]
 
     result = await parser.parse_metadata(metadata)
 
@@ -272,7 +272,7 @@ async def test_parse_metadata_handles_modelVersionIds(monkeypatch):
         "modelVersionIds": [2398829, 2398838],
     }
 
-    assert parser.is_metadata_matching(metadata)
+    assert parser.is_metadata_matching(metadata)  # pyright: ignore[reportArgumentType]
 
     result = await parser.parse_metadata(metadata)