/**
 * Atomic JSON store for `<dataDir>/update-state.json`.
 *
 * Mirrors `NatStore`: load on demand, write to
 * `<path>.tmp` then rename. Single-writer assumption — only one cadre-host
 * process owns a given dataDir.
 */
import { type UpdateState } from './types.js';
export declare class UpdateStateStore {
    private readonly path;
    private cache;
    constructor(rootDir: string);
    filePath(): string;
    /** Load (with caching). A missing file returns an empty state. */
    load(): UpdateState;
    /** Persist a new state atomically. */
    save(state: UpdateState): void;
    /** Merge a patch into the current state and persist. */
    update(patch: Partial<Omit<UpdateState, 'version'>>): UpdateState;
    /** Drop a specific field from the persisted state. */
    clearField<K extends keyof Omit<UpdateState, 'version'>>(field: K): UpdateState;
}