export interface BackupDatabaseOptions {
    /** Why this backup is being taken (e.g. "pre-migration", "daily"). Debounce and retention are tracked per reason. */
    reason: string;
    /** How many backups to retain per reason (newest first). */
    keep?: number;
    /** Source database file; defaults to the live store path. Tests must pass a temp path. */
    dbFile?: string;
    /** Directory for backup files; defaults to `<db dir>/backups`. */
    backupsDir?: string;
    /** Injectable clock for tests. */
    now?: Date;
}
export interface BackupDatabaseResult {
    /** Absolute path of the backup that was written (absent when skipped). */
    path?: string;
    skipped: boolean;
    skipReason?: string;
    /** Backups removed by retention pruning. */
    prunedPaths: string[];
}
/**
 * Snapshot the loops database with `VACUUM INTO`. Per-reason backups are
 * debounced to at most one per hour and pruned to the `keep` most recent.
 */
export declare function backupDatabase(opts: BackupDatabaseOptions): BackupDatabaseResult;