feat(teacher-bff): 添加视口聚合端点 + 修复身份头读取

- 新增 GET /teacher/viewports 聚合 IAM 视口配置
- 修复 controller 从 x-user-id header 读取身份（替代 AuthenticatedRequest）
- 添加 zod + @types/express 依赖

services/teacher-bff/src/teacher/teacher.service.ts

@@ -1,22 +1,52 @@
-import { Injectable } from '@nestjs/common';
-import { env } from '../config/env.js';
+import { Injectable } from "@nestjs/common";
+import { env } from "../config/env.js";
+
+export interface ViewportItem {
+  key: string;
+  label: string;
+  route: string;
+  icon: string | null;
+  sortOrder: string;
+  requiredPermission: string | null;
+}
 
 @Injectable()
 export class TeacherService {
   // 聚合 IAM + classes 服务的数据
-  async getDashboard(userId: string): Promise<unknown> {
+  async getDashboard(userId: string): Promise<{
+    user: unknown;
+    classes: unknown;
+  }> {
     const [iamRes, classesRes] = await Promise.allSettled([
       fetch(`${env.IamServiceUrl}/iam/me`, {
-        headers: { 'x-user-id': userId },
+        headers: { "x-user-id": userId },
       }),
       fetch(`${env.ClassesServiceUrl}/classes`, {
-        headers: { 'x-user-id': userId },
+        headers: { "x-user-id": userId },
       }),
     ]);
 
     return {
-      user: iamRes.status === 'fulfilled' ? await iamRes.value.json() : null,
-      classes: classesRes.status === 'fulfilled' ? await classesRes.value.json() : null,
+      user: iamRes.status === "fulfilled" ? await iamRes.value.json() : null,
+      classes:
+        classesRes.status === "fulfilled"
+          ? await classesRes.value.json()
+          : null,
     };
   }
+
+  // 聚合 IAM 视口配置（L1 导航）
+  async getViewports(userId: string): Promise<ViewportItem[]> {
+    const res = await fetch(`${env.IamServiceUrl}/iam/viewports`, {
+      headers: { "x-user-id": userId },
+    });
+    if (!res.ok) {
+      return [];
+    }
+    const json = (await res.json()) as {
+      success: boolean;
+      data?: ViewportItem[];
+    };
+    return json.data ?? [];
+  }
 }