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/nodes/test_utils.py

@@ -34,7 +34,7 @@ class _DummyModel:
 
 
 def test_nunchaku_load_lora_skips_missing_lora(monkeypatch, caplog):
-    import folder_paths
+    import folder_paths  # pyright: ignore[reportMissingImports]
 
     dummy_model = _DummyModel()