/**
 * `absolute tunnel-relay` — run the public reverse-tunnel relay (typically on a
 * small always-on host like a DO App Platform service). Dev machines connect to
 * it with `dev: { tunnel: { relay, token } }`. Reads:
 *   - PORT (App Platform injects this; default 8787)
 *   - ABSOLUTE_TUNNEL_TOKEN (required shared secret)
 *   - ABSOLUTE_TUNNEL_PUBLIC_URL (optional; the relay's public base URL)
 */
export declare const tunnelRelay: () => void;