/**
 * Status History — records PipelineInstance status transitions (AC-3.7).
 *
 * Every status change on a PipelineInstance must go through this helper
 * to ensure the transition is appended to statusHistory.
 */
import type { PipelineInstance, PipelineInstanceStatus } from '../types/index.js';
/**
 * Transition a PipelineInstance to a new status, recording the change
 * in statusHistory. Mutates the instance in place and returns it.
 *
 * @param instance - The pipeline instance to transition.
 * @param to - Target status.
 * @param trigger - What caused the transition (e.g. 'advance', 'pause', 'cancel').
 * @param now - Optional timestamp override for testing.
 */
export declare function transitionInstanceStatus(instance: PipelineInstance, to: PipelineInstanceStatus, trigger: string, now?: string): PipelineInstance;
//# sourceMappingURL=status-history.d.ts.map