Function spawn_headless_run_driver 

pub fn spawn_headless_run_driver(
    config: Config,
    engine: Arc<Mutex<SopEngine>>,
    audit: Option<Arc<SopAuditLogger>>,
    first_action: SopRunAction,
)

Spawn a background task that drives a resumed SOP action to its next blocking or terminal state. Gate-clearing surfaces without an ambient agent turn (HTTP decide, WS approvals, manual dashboard runs) land here: ExecuteStep runs through a fresh agent loop under the step’s resolved agent, DeterministicStep routes through the engine’s headless deterministic driver, and every other action is already parked or terminal.