feat(teacher-portal): 实现登录页侧边栏路由组与真实JWT集成

- lib/auth.ts: localStorage token 存储 + login/logout

- app/login: 登录表单页

- components/AppShell: 视口驱动侧边栏 + 路由保护

- app/(app)/layout: 路由组布局套 AppShell

- app/(app)/dashboard: 聚合统计卡片页

- app/(app)/classes: 迁移 CRUD 改用真实 JWT

- app/page.tsx: 根路径重定向

- known-issues.md: 记录 P2 经验

apps/teacher-portal/src/lib/auth.ts

@@ -0,0 +1,77 @@
+// 认证工具：token 存储 + 路由保护
+
+const TOKEN_KEY = "edu_access_token";
+const USER_KEY = "edu_user_info";
+
+export interface UserInfo {
+  id: string;
+  email: string;
+  name: string;
+  roles: string[];
+  permissions: string[];
+  dataScope: string;
+}
+
+export function getToken(): string | null {
+  if (typeof window === "undefined") return null;
+  return localStorage.getItem(TOKEN_KEY);
+}
+
+export function setToken(token: string): void {
+  if (typeof window === "undefined") return;
+  localStorage.setItem(TOKEN_KEY, token);
+}
+
+export function clearToken(): void {
+  if (typeof window === "undefined") return;
+  localStorage.removeItem(TOKEN_KEY);
+  localStorage.removeItem(USER_KEY);
+}
+
+export function getUser(): UserInfo | null {
+  if (typeof window === "undefined") return null;
+  const raw = localStorage.getItem(USER_KEY);
+  if (!raw) return null;
+  try {
+    return JSON.parse(raw) as UserInfo;
+  } catch {
+    return null;
+  }
+}
+
+export function setUser(user: UserInfo): void {
+  if (typeof window === "undefined") return;
+  localStorage.setItem(USER_KEY, JSON.stringify(user));
+}
+
+export function isAuthenticated(): boolean {
+  return getToken() !== null;
+}
+
+// 调用 Gateway 登录接口
+export async function login(
+  email: string,
+  password: string,
+): Promise<{ user: UserInfo; token: string }> {
+  const res = await fetch("/api/v1/iam/login", {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({ email, password }),
+  });
+  const json = await res.json();
+  if (!json.success) {
+    throw new Error(json.error?.message || "登录失败");
+  }
+  const user = json.data.user as UserInfo;
+  const token = json.data.tokens.accessToken as string;
+  setToken(token);
+  setUser(user);
+  return { user, token };
+}
+
+export function logout(): void {
+  clearToken();
+  if (typeof window !== "undefined") {
+    window.location.href = "/login";
+  }
+}