/**
 * @module queue/drain
 *
 * Drains the follow-up queue after an koi run completes. In "collect" mode,
 * batches same-channel messages into a single prompt; in other modes, processes
 * items individually. Handles cross-channel routing by falling back to
 * per-item processing when messages span different channels/targets.
 */
import type { FollowupRun } from "./types.js";
export declare function scheduleFollowupDrain(key: string, runFollowup: (run: FollowupRun) => Promise<void>): void;