Function run_deliverer 

pub async fn run_deliverer(
    rx: Receiver<Event>,
    targets: Receiver<Arc<Vec<WebhookTarget>>>,
    obs: Arc<Observability>,
    shutdown: Receiver<()>,
    durability: Option<Arc<dyn EventDurability>>,
)

The deliverer loop (DW-044): drain the bus, filter by kind, dispatch one bounded-concurrency delivery task per (event, target). Returns on shutdown (pending queue abandoned — documented: the gateway is not a durable queue) or when the bus closes.

REL-14 (#249): when a durability layer is provided, the deliverer marks each event as acked after dispatching to matching targets. This gives at-least-once semantics on restart: an event that was persisted to the WAL but not yet acked is replayed on the next startup.

Spawned by the DataPlane (DataPlane::spawn_webhook_deliverer) so the binary and tests share one wiring path.