/**
 * Returns false when we cannot verify origin storage headroom, or when storage is
 * nearly full, so we skip y-indexeddb before `indexedDB.open` can throw
 * QuotaExceededError (e.g. user disk full). Local IDB is optional — server state
 * is authoritative — so we fail closed when `estimate` is missing or inconclusive.
 */
export declare const hasIndexedDBStorageHeadroom: () => Promise<boolean>;
/**
 * Clear stale IndexedDB Y.Doc cache before connecting to Hocuspocus.
 * Platform persists authoritative state on the server; merging local IDB + server
 * snapshots on refresh duplicates document content in the Y.Doc.
 *
 * Uses `clearDocument` (deleteDB) so we never open/load the stale cache first.
 * Returns true only when the DB was deleted; callers must not attach
 * IndexeddbPersistence over an uncleared room.
 */
export declare const clearIndexedDBCacheForRoom: (room: string) => Promise<boolean>;