/**
 * Database Client
 *
 * Lazy-initialized Turso/libSQL client.
 * Returns null when not configured — all callers handle this gracefully.
 *
 * `@libsql/client` is an *optional* peer dependency, so it is imported at
 * initialization time rather than at module load: a top-level value import
 * here would make `import "@diegoaltoworks/talker"` throw for a host that
 * installed only hono (see src/peer-deps.test.ts, which enforces this across
 * the source tree). A host that configures a database URL but never installed
 * the driver gets an actionable error naming the package.
 */
import type { Client } from "@libsql/client";
/**
 * Initialize the database client from config.
 * Called once during setup; subsequent calls to getDbClient() return the cached client.
 *
 * Throws when `@libsql/client` is not installed — a configured database with
 * no driver is a deployment mistake, not a runtime condition to degrade past.
 * Other connection failures keep the historical behavior: logged, client stays
 * null, callers carry on without persistence.
 */
export declare function initDbClient(url: string, authToken: string): Promise<void>;
/**
 * Set the database client directly (for testing with mock/in-memory clients).
 */
export declare function setDbClient(mockClient: Client | null): void;
/**
 * Get the database client. Returns null if not configured.
 */
export declare function getDbClient(): Client | null;
/**
 * Close the database client.
 */
export declare function closeDbClient(): Promise<void>;