/**
 * Scheduled function that runs daily to check for expired subscriptions
 * and update custom claims with expired status.
 *
 * **Architecture decision — opt-in scheduled function:**
 * This function is not automatically deployed. Consumer apps opt in by
 * exporting it from their functions entry point (e.g. `index.ts`). If not
 * exported, Firebase never schedules it.
 *
 * The `users` collection path defaults to `'users'` but is configurable via
 * the `USERS_COLLECTION_PATH` environment variable, allowing consumers to
 * use their own collection structure (e.g. `'app_users'`, `'tenants/{id}/users'`).
 */
export declare const checkExpiredSubscriptions: import("firebase-functions/scheduler").ScheduleFunction;
