Function spawn 

pub(crate) fn spawn(
    feed: Arc<FleetFeed>,
    id_store: Arc<Store>,
    config: Arc<ConfigState>,
    headless: bool,
    token: CancellationToken,
)

Start the publisher. No-op without a WAN identity store (nothing to sign with). headless is srv’s --headless (policy). Stops with token (srv shutdown).