/**
 * Enqueue for the application delivery outbox (WFT-85): validating an offered
 * delivery, resolving its idempotency identity, enforcing backlog capacity,
 * and committing the record with its indexes and fleet event.
 *
 * Enqueue is the one transition that also allocates: it advances the outbox
 * header's sequence and open count in the same conditional batch as the record
 * itself, so backlog accounting can never drift from the records it describes.
 *
 * @module core/outbox-enqueue
 */
import type { ApplicationDeliveryAdmission, ApplicationDeliveryInput, OutboxCapacity } from './outbox-contract.ts';
import { type OutboxRuntime } from './outbox-internals.ts';
/** Backlog accounting, shared by enqueue rejection and the public `capacity()`. */
export declare function capacityOf(runtime: OutboxRuntime, open: number, enqueued: number): OutboxCapacity;
/**
 * Offer a delivery to the outbox.
 *
 * An exact retry of the same idempotency identity returns the original
 * receipt. Reusing the key with a different destination, kind, or payload
 * digest returns a conflict and leaves the original untouched. A full backlog
 * is rejected before anything is persisted.
 */
export declare function enqueueDelivery(runtime: OutboxRuntime, delivery: ApplicationDeliveryInput): Promise<ApplicationDeliveryAdmission>;