/**
 * Portal WebSocket layer — mounts on the existing HTTP server, routes the
 * `upgrade` event by URL path, and bridges browser frames + input events
 * between the canvas Portal node and a Playwright session.
 *
 *   Server  → Client  /portal/:id/screencast    JPEG frames + url notifications
 *   Client  → Server  /portal/:id/input          mouse / keyboard / wheel
 *
 * Frame protocol (text JSON):
 *   { "type": "frame",  "data": "<base64 JPEG>", "viewport": { "w": ..., "h": ... } }
 *   { "type": "url",    "url":  "https://..." }
 *   { "type": "error",  "error": "..." }
 *
 * Input protocol (text JSON, client → server):
 *   { "type": "mousemove", "x": 0..1, "y": 0..1 }                   (normalized)
 *   { "type": "mousedown" | "mouseup", "x", "y", "button": "left" | "middle" | "right" }
 *   { "type": "wheel",     "x", "y", "deltaX", "deltaY" }
 *   { "type": "keydown" | "keyup", "key": "a" | "Enter" | ... }
 *   { "type": "type",      "text": "..." }                          (raw text input)
 *   { "type": "navigate",  "url": "..." }
 */
import type { Server as HttpServer } from "node:http";
/**
 * Mount the portal WebSocket handlers on the given HTTP server. Call once
 * after `app.listen()`. The function is idempotent — repeated calls overwrite
 * the previous listener.
 */
export declare function attachPortalWebSockets(server: HttpServer): void;