/**
 * The index persistence seam (L1.5). MemoryIndexStore is session-scoped and
 * lazy; an opaque-blob backend implements the same interface so the
 * collection call-site is unchanged.
 */
import { InvertedIndex, type IndexDoc } from './inverted-index.js';
export interface IndexStore {
    ensureBuilt(build: () => ReadonlyArray<IndexDoc>): Promise<InvertedIndex>;
    markDirty(): void;
    flush(): Promise<void>;
    readonly built: boolean;
}
export declare class MemoryIndexStore implements IndexStore {
    private index;
    get built(): boolean;
    ensureBuilt(build: () => ReadonlyArray<IndexDoc>): Promise<InvertedIndex>;
    markDirty(): void;
    flush(): Promise<void>;
}