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_scanner_base_models.py

@@ -3,13 +3,19 @@ from types import SimpleNamespace
 import pytest
 
 from py.services.model_scanner import ModelScanner
+from py.utils.models import BaseModelMetadata
 
 
-class DummyScanner:
+class DummyScanner(ModelScanner):
     def __init__(self, raw_data):
+        super().__init__(
+            model_type="dummy",
+            model_class=BaseModelMetadata,
+            file_extensions={".safetensors"},
+        )
         self._cache = SimpleNamespace(raw_data=raw_data)
 
-    async def get_cached_data(self):
+    async def get_cached_data(self, force_refresh: bool = False, rebuild_cache: bool = False):
         return self._cache