Function spawn_init_watcher 

pub fn spawn_init_watcher(
    loader: PluginLoaderHandle,
    init_dir: PathBuf,
    runtime: &Handle,
)

Spawn the init-artifact auto-reload watcher on runtime. Watches init_dir (non-recursively) and sync_inits the loader on every settled change. A watcher that can’t be created / can’t watch the dir is a logged warning that disables auto-reload (manual :reload-config still works), never a failure. No-op if init_dir doesn’t exist (nothing to watch until the user creates a config; a restart picks it up).