feat(framework): net Transport 接口 + 测试用 FakeTransport

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

cocoscreator_projects/framework-tests/helpers/fake-transport.ts

@@ -0,0 +1,27 @@
+import type { Transport } from '../../YouleNexus/assets/framework/net/transport.ts';
+
+/** 内存 Transport：模拟服务器。用 microtask 队列异步触发回调，贴近真实 WS 时序。 */
+export class FakeTransport implements Transport {
+  sent: string[] = [];
+  url = '';
+  private openCb?: () => void;
+  private msgCb?: (f: string) => void;
+  private closeCb?: () => void;
+  private pending: Array<() => void> = [];
+  private closed = false;
+
+  connect(url: string): void { this.url = url; this.pending.push(() => this.openCb?.()); }
+  send(frame: string): void { if (!this.closed) this.sent.push(frame); }
+  close(): void { if (this.closed) return; this.closed = true; this.pending.push(() => this.closeCb?.()); }
+  onOpen(cb: () => void): void { this.openCb = cb; }
+  onMessage(cb: (f: string) => void): void { this.msgCb = cb; }
+  onClose(cb: () => void): void { this.closeCb = cb; }
+
+  /** 测试侧：模拟服务器推一帧给客户端。 */
+  serverPush(frame: string): void { if (!this.closed) this.pending.push(() => this.msgCb?.(frame)); }
+
+  /** 冲刷所有挂起回调（解析微任务）。 */
+  async flush(): Promise<void> {
+    while (this.pending.length) { const fn = this.pending.shift()!; fn(); await Promise.resolve(); }
+  }
+}