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_check_pending_models.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 
 import json
 from types import SimpleNamespace
+from typing import Any
 
 import pytest
 
@@ -13,7 +14,7 @@ from py.utils import example_images_download_manager as download_module
 class StubScanner:
     """Scanner double returning predetermined cache contents."""
 
-    def __init__(self, models: list[dict]) -> None:
+    def __init__(self, models: list[dict[str, Any]]) -> None:
         self._cache = SimpleNamespace(raw_data=models)
 
     async def get_cached_data(self):
@@ -58,9 +59,9 @@ class RecordingWebSocketManager:
     """Collects broadcast payloads for assertions."""
 
     def __init__(self) -> None:
-        self.payloads: list[dict] = []
+        self.payloads: list[dict[str, Any]] = []
 
-    async def broadcast(self, payload: dict) -> None:
+    async def broadcast(self, payload: dict[str, Any]) -> None:
         self.payloads.append(payload)