- Updated error handling in `nd_host_scheduler.go`, `nd_host_websocket.go`, `nd_host_artwork.go`, `nd_host_cache.go`, and `nd_host_subsonicapi.go` to convert string errors from responses into Go errors.
- Removed redundant error checks in test data plugins for cleaner code.
- Ensured consistent error handling across all plugins to improve reliability and maintainability.