feat(framework): Cocos/浏览器 WebSocket Transport adapter

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

cocoscreator_projects/YouleNexus/assets/framework/net/cocos-transport.ts

@@ -0,0 +1,23 @@
+import type { Transport } from './transport.ts';
+
+/** 生产用 Transport：包装运行时全局 WebSocket（Cocos 原生/浏览器）。docs/protocol/01 §2。 */
+export class CocosWebSocketTransport implements Transport {
+  private ws: WebSocket | null = null;
+  private openCb?: () => void;
+  private msgCb?: (frame: string) => void;
+  private closeCb?: () => void;
+
+  connect(url: string): void {
+    const ws = new WebSocket(url);            // url 形如 ws://ip:port
+    this.ws = ws;
+    ws.onopen = () => this.openCb?.();
+    ws.onmessage = (ev: MessageEvent) => this.msgCb?.(typeof ev.data === 'string' ? ev.data : String(ev.data));
+    ws.onclose = () => this.closeCb?.();
+    ws.onerror = () => { try { ws.close(); } catch { /* ignore */ } };
+  }
+  send(frame: string): void { this.ws?.send(frame); }
+  close(): void { try { this.ws?.close(); } catch { /* ignore */ } }
+  onOpen(cb: () => void): void { this.openCb = cb; }
+  onMessage(cb: (frame: string) => void): void { this.msgCb = cb; }
+  onClose(cb: () => void): void { this.closeCb = cb; }
+}