/**
 * shutdown.ts — 统一 Graceful Shutdown 协调器
 *
 * 所有入口（mcp-server / api-server / cli）共用同一个 shutdown 协调器，
 * 避免各入口重复编写 signal handler 并确保：
 *   1. 防重入 — 多次信号只执行一轮 shutdown
 *   2. 倒序执行 — 后注册的 hook 先关闭（类似栈 LIFO）
 *   3. 强制超时 — 超过 TIMEOUT 强杀进程（默认 10 秒）
 *   4. WAL checkpoint — DB 关闭前刷盘
 *   5. hook 隔离 — 单个 hook 失败不阻断后续 hook 执行
 *
 * @module shared/shutdown
 *
 * @example
 *   import { shutdown } from '#shared/shutdown.js';
 *
 *   shutdown.install();
 *   shutdown.register(() => db.close());
 *   shutdown.register(async () => await server.drain());
 */
/** Async or sync cleanup function */
type ShutdownHook = () => Promise<void> | void;
declare class ShutdownCoordinator {
    #private;
    /**
     * Register a shutdown hook.
     *
     * Hooks execute in **reverse** registration order (LIFO):
     * last registered = first executed.
     *
     * @param fn   Cleanup function (sync or async)
     * @param label  Human-readable label for logging (e.g. 'database', 'http-server')
     */
    register(fn: ShutdownHook, label?: string): void;
    /**
     * Set the forced-exit timeout.
     * @default 10_000 (10 seconds)
     */
    setTimeout(ms: number): void;
    /**
     * Execute all registered hooks in reverse order, then exit.
     * Safe to call multiple times — only the first invocation runs.
     *
     * @param signal The signal or reason string (for logging)
     */
    execute(signal: string): Promise<void>;
    /**
     * Install SIGTERM + SIGINT handlers on the current process.
     * Call this once, early in the entry's lifecycle.
     */
    install(): void;
    /** Whether a shutdown is currently in progress */
    get isShuttingDown(): boolean;
    /** Number of registered hooks (for testing / diagnostics) */
    get hookCount(): number;
}
/**
 * Singleton shutdown coordinator.
 * Import and use across all entry points and modules.
 */
export declare const shutdown: ShutdownCoordinator;
export {};