/**
 * hmem v2 — database connection, schema bootstrap, and migrations runner.
 *
 * Opens a better-sqlite3 handle in WAL mode, instantiates the locked v2 schema
 * (`schema-v2.sql`) on first open, stamps `schema_version.schema_major = '2'`
 * (Phase 6 sync gates push/pull on this value), and runs an append-only list of
 * forward migrations idempotently (mirrors v1's `schema_version`-keyed pattern).
 */
import Database from 'better-sqlite3';
/**
 * Thrown by openDb() when asked to open an existing **v1** store
 * (`memories`/`memory_nodes`). The v2 open path must never v2-stamp such a file —
 * doing so injects empty v2 tables next to the real v1 data and corrupts it into
 * an unreadable hybrid (v2 reads query `entries`, see 0 rows; real data sits unread
 * in `memories`). Symmetric corruption-prevention dual of HmemStore's v2-file guard
 * (commit 44fd3dc). Callers that can tolerate a v1 file (hooks, the MCP tool boundary)
 * catch this and no-op / surface a "run `hmem migrate`" hint; others let it propagate
 * as a clear fatal.
 */
export declare class V1FileError extends Error {
    constructor(message: string);
}
export declare function openDb(path: string): Database.Database;
export declare function getSchemaMajor(db: Database.Database): string | null;
export declare function runMigrations(db: Database.Database): void;