Function spawn_scheduler 

pub fn spawn_scheduler(
    connectors: Arc<Vec<ConnectorConfig>>,
    roots: Arc<HashMap<String, String>>,
    default_workspace_id: String,
    state_dir: PathBuf,
    data_dir: PathBuf,
    quota_bytes: u64,
    tick: Duration,
)

Spawn the background scheduler. Ticks every tick, runs each due connector once (blocking work on the blocking pool), and records its outcome. A no-op when no connectors are configured.