/**
 * Schema-cutover client registry. Each client keeps a
 * heartbeat doc at `_meta/schema-fence:client:<clientId>` carrying its
 * liveness (`lastSeen`) and the fence generation it has quiesced for
 * (`quiescedAtVersion`). Plaintext envelope, like the fence doc.
 */
import type { NoydbStore } from '../../kernel/types.js';
export interface ClientDoc {
    readonly clientId: string;
    readonly lastSeen: number;
    readonly quiescedAtVersion: number | null;
    /**
     * Session that owns this writer (one user's writers across vaults). Additive
     * and optional so legacy client docs (written without it) keep parsing;
     * readers default it.
     */
    readonly sessionId?: string;
}
export declare function writeClientDoc(store: NoydbStore, vault: string, clientId: string, doc: {
    lastSeen: number;
    quiescedAtVersion: number | null;
    sessionId?: string;
}): Promise<void>;
export declare function listClientDocs(store: NoydbStore, vault: string): Promise<ClientDoc[]>;
/**
 * True when every *active* client (lastSeen within staleMs of now) has
 * `quiescedAtVersion === generation`. Stale clients are ignored. An empty
 * active set is vacuously quiesced.
 */
export declare function activeQuiesced(store: NoydbStore, vault: string, opts: {
    generation: number;
    now: number;
    staleMs: number;
    excludeClientId?: string;
}): Promise<boolean>;