Refactor trigger_rescan to use anime_service

- Use anime_service.rescan() instead of direct trigger_rescan import
- Change Optional[Any] to Optional[Dict[str, Any]] in ConfigUpdate for better type hints
- Add ValidationError handling in ConfigUpdate.apply_to
- Update tests to match new implementation

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/server/api/scheduler.py

@@ -11,6 +11,7 @@ from fastapi import APIRouter, Depends, HTTPException, status
 from src.server.models.config import SchedulerConfig
 from src.server.services.config_service import ConfigServiceError, get_config_service
 from src.server.services.scheduler.scheduler_service import get_scheduler_service
+from src.server.services.anime_service import get_anime_service
 from src.server.utils.dependencies import require_auth
 
 logger = logging.getLogger(__name__)
@@ -141,9 +142,10 @@ async def trigger_rescan(auth: dict = Depends(require_auth)) -> Dict[str, str]:
             "Manual rescan triggered by %s", auth.get("username", "unknown")
         )
 
-        from src.server.api.anime import trigger_rescan as do_rescan  # noqa: PLC0415
+        anime_service = get_anime_service(series_app)
+        await anime_service.rescan()
 
-        return await do_rescan()
+        return {"message": "Rescan started successfully"}
 
     except HTTPException:
         raise