docs(admin-portal): 新增 nextstep-v2.md 记录下游核查结果

v1 声称完成的下游工作经核查实际未完成：
- api-gateway: /api/admin/graphql 路由未注册，go vet 编译失败
- teacher-bff: resolver 已完成但 schema 未同步（命名空间 vs 扁平）
- iam: proto 缺 BatchGetUsers rpc 声明

v2 记录详细核查证据和修复要求

apps/teacher-portal/vitest.setup.ts

@@ -0,0 +1,84 @@
+/**
+ * Vitest 全局测试 setup
+ *
+ * - 注册 @testing-library/jest-dom 自定义匹配器
+ * - mock next/navigation（App Router hooks）
+ * - polyfill BroadcastChannel / WebSocket（jsdom 未实现）
+ * - 启动/重置/关闭 MSW server
+ */
+import "@testing-library/jest-dom/vitest";
+import { afterAll, afterEach, beforeAll, beforeEach, vi } from "vitest";
+import { server } from "./src/mocks/server";
+
+// mock next/navigation（App Router hooks 依赖）
+vi.mock("next/navigation", () => ({
+  useParams: () => ({}),
+  useRouter: () => ({
+    push: vi.fn(),
+    replace: vi.fn(),
+    back: vi.fn(),
+    forward: vi.fn(),
+    refresh: vi.fn(),
+    prefetch: vi.fn(),
+  }),
+  useSearchParams: () => new URLSearchParams(),
+  usePathname: () => "/",
+  redirect: vi.fn(),
+  notFound: vi.fn(),
+}));
+
+// btoa Unicode 兼容 polyfill 已移至 vitest.polyfills.ts（需在 server import 之前生效）
+
+// BroadcastChannel polyfill（jsdom 未实现 BroadcastChannel）
+if (typeof globalThis.BroadcastChannel === "undefined") {
+  class MockBroadcastChannel {
+    name: string;
+    onmessage: ((event: MessageEvent) => void) | null = null;
+    constructor(name: string) {
+      this.name = name;
+    }
+    addEventListener(): void {}
+    removeEventListener(): void {}
+    postMessage(): void {}
+    close(): void {}
+  }
+  // 测试中需要 as 断言将 mock 类挂载到全局
+  globalThis.BroadcastChannel =
+    MockBroadcastChannel as unknown as typeof BroadcastChannel;
+}
+
+// WebSocket polyfill（jsdom 未实现 WebSocket）
+if (typeof globalThis.WebSocket === "undefined") {
+  class MockWebSocket {
+    static CONNECTING = 0;
+    static OPEN = 1;
+    static CLOSING = 2;
+    static CLOSED = 3;
+    url: string;
+    onopen: ((event: Event) => void) | null = null;
+    onmessage: ((event: MessageEvent) => void) | null = null;
+    onerror: ((event: Event) => void) | null = null;
+    onclose: ((event: CloseEvent) => void) | null = null;
+    readyState = 0;
+    constructor(url: string) {
+      this.url = url;
+    }
+    send(): void {}
+    close(): void {}
+  }
+  globalThis.WebSocket = MockWebSocket as unknown as typeof WebSocket;
+}
+
+// 启动 MSW server（拦截 HTTP 请求返回 mock 响应）
+beforeAll(() => server.listen({ onUnhandledRequest: "bypass" }));
+
+// 每个测试后恢复初始 MSW handlers（隔离测试间状态）
+afterEach(() => server.restoreHandlers());
+
+// 全部测试完成后关闭 MSW server
+afterAll(() => server.close());
+
+// 每个测试前清理 localStorage（防止测试间状态泄漏）
+beforeEach(() => {
+  localStorage.clear();
+});