/**
 * Exports all Project, Task, and Knowledge nodes and relationships to JSON files.
 * Also creates a full-export.json file containing all data in a single file.
 * Also manages backup rotation.
 * @returns The path to the directory containing the backup files.
 * @throws Error if the export step fails. Rotation errors are logged but don't throw.
 */
export declare const exportDatabase: () => Promise<string>;
/**
 * Imports data from JSON files, overwriting the existing database.
 * Can import from either full-export.json (if it exists) or individual entity files.
 * @param backupDir The path to the directory containing the backup JSON files.
 * @throws Error if any step fails.
 */
export declare const importDatabase: (backupDir: string) => Promise<void>;