feat(portal-shell): 教师域考试管理页面迁移（P2）

按 ARCHITECTURE.md §9.1/§10 P2 要求，迁移教师域 exams 模块：
- 列表页 /shell/teacher/exams（ListPageShell + URL 状态 + 客户端二次筛选）
- 详情页 /shell/teacher/exams/[id]（DetailPageShell + 真实 exam(id) 查询）
- 新建页 /shell/teacher/exams/new（FormPageShell + MSW 兜底）
- 纯函数 transformations.ts + 19 个 vitest 单测
- @contract-pending：exams(classId) 列表查询、createExam mutation 走 MSW
- 三态 UI（loading/error/empty）+ 路由级 loading.tsx/error.tsx
- i18n：zh-CN/en 双语补全，无硬编码中文
- MSW handlers 支持 variables 透传

§11.3 DoD 验收：
- lint: 0 errors（4 个 __generated__ 预存警告）
- typecheck: 0 errors
- test: 250/250 passed（含 19 个新增 transformations 测试）
- lint:tokens: 0 errors

apps/portal-shell/src/app/api/graphql/route.ts

@@ -59,10 +59,12 @@ export async function POST(req: NextRequest): Promise<NextResponse> {
   if (MSW_ENABLED) {
     const body = (await req.json().catch(() => ({}))) as {
       operationName?: string;
+      variables?: Record<string, unknown>;
     };
-    return NextResponse.json(graphqlResponse(body.operationName), {
-      headers: { "Cache-Control": "no-store" },
-    });
+    return NextResponse.json(
+      graphqlResponse(body.operationName, body.variables),
+      { headers: { "Cache-Control": "no-store" } },
+    );
   }
 
   const cookieHeader = req.headers.get("cookie");

apps/portal-shell/src/app/shell/teacher/exams/[id]/page.tsx

@@ -0,0 +1,22 @@
+import { Suspense } from "react";
+
+import { ExamDetailClient } from "@/features/teacher/exams/exam-detail-client";
+import { DetailPageSkeleton } from "@/shared/components/page-templates";
+
+/**
+ * 考试详情页（ARCHITECTURE.md §7.3 详情页 / §9.1 / §10 P2）
+ *
+ * Server Component 入口：仅负责 Suspense 边界包裹。
+ * 业务逻辑在 ExamDetailClient（client component）中。
+ *
+ * 数据契约：单查 exam(id: ID!) ✅ schema 真实字段（core-edu 子图）
+ *
+ * 关联：ARCHITECTURE.md §5.5 / §7.3 / §9.1 / §10 P2 / §11.3
+ */
+export default function ExamDetailPage(): React.ReactElement {
+  return (
+    <Suspense fallback={<DetailPageSkeleton />}>
+      <ExamDetailClient />
+    </Suspense>
+  );
+}

apps/portal-shell/src/app/shell/teacher/exams/error.tsx

@@ -0,0 +1,33 @@
+"use client";
+
+/**
+ * 考试路由错误边界（ARCHITECTURE.md §7.4 三态规范 / §11.3 DoD）。
+ * Next.js Route Segment error.tsx，捕获子树未处理异常。
+ */
+import { useEffect } from "react";
+
+import { Button } from "@/shared/components/ui/button";
+
+export default function ExamsError({
+  error,
+  reset,
+}: {
+  error: Error & { digest?: string };
+  reset: () => void;
+}): React.ReactElement {
+  useEffect(() => {
+    console.error("[portal-shell] exams route error:", error);
+  }, [error]);
+
+  return (
+    <div className="flex flex-col items-center justify-center gap-4 rounded-xl border border-destructive/30 bg-destructive/5 p-10">
+      <h2 className="text-lg font-semibold text-destructive">考试页面出错了</h2>
+      <p className="text-sm text-muted-foreground">
+        {error.message || "未知错误"}
+      </p>
+      <Button onClick={reset} variant="outline">
+        重试
+      </Button>
+    </div>
+  );
+}

apps/portal-shell/src/app/shell/teacher/exams/loading.tsx

@@ -0,0 +1,9 @@
+import { ListPageSkeleton } from "@/shared/components/page-templates";
+
+/**
+ * 考试列表页加载骨架（ARCHITECTURE.md §7.4 三态规范 / §11.3 DoD）。
+ * Next.js Route Segment loading.tsx，自动包裹页面渲染期间。
+ */
+export default function ExamsLoading(): React.ReactElement {
+  return <ListPageSkeleton rows={5} />;
+}

apps/portal-shell/src/app/shell/teacher/exams/new/page.tsx

@@ -0,0 +1,23 @@
+import { Suspense } from "react";
+
+import { NewExamClient } from "@/features/teacher/exams/new-exam-client";
+import { FormPageSkeleton } from "@/shared/components/page-templates";
+
+/**
+ * 新建考试表单页（ARCHITECTURE.md §7.3 表单页 / §9.1 / §10 P2）
+ *
+ * Server Component 入口：仅负责 Suspense 边界包裹（useSearchParams 要求）。
+ * 业务逻辑在 NewExamClient（client component）中。
+ *
+ * 数据契约：mutation createExam(input) ❌ schema 无 Mutation → MSW 兜底（@contract-pending）
+ * 契约工单：docs/architecture/issues/contracts/core-edu_contract.md#create-exam-mutation
+ *
+ * 关联：ARCHITECTURE.md §5.3 / §5.4 / §7.3 / §9.1 / §10 P2 / §11.3 / §11.4
+ */
+export default function NewExamPage(): React.ReactElement {
+  return (
+    <Suspense fallback={<FormPageSkeleton />}>
+      <NewExamClient />
+    </Suspense>
+  );
+}

apps/portal-shell/src/app/shell/teacher/exams/page.tsx

@@ -0,0 +1,23 @@
+import { Suspense } from "react";
+
+import { ExamsListClient } from "@/features/teacher/exams/exams-list-client";
+import { ListPageSkeleton } from "@/shared/components/page-templates";
+
+/**
+ * 考试管理列表页（ARCHITECTURE.md §7.3 列表页 / §9.1 / §10 P2）
+ *
+ * Server Component 入口：仅负责 Suspense 边界包裹（useSearchParams 要求）。
+ * 业务逻辑在 ExamsListClient（client component）中。
+ *
+ * 数据契约：列表查询 exams(classId) ❌ schema 无此字段 → MSW 兜底（@contract-pending）
+ * 契约工单：docs/architecture/issues/contracts/core-edu_contract.md#exams-list
+ *
+ * 关联：ARCHITECTURE.md §5.3 / §5.4 / §7.3 / §9.1 / §10 P2 / §11.3 / §11.4
+ */
+export default function ExamsListPage(): React.ReactElement {
+  return (
+    <Suspense fallback={<ListPageSkeleton rows={5} />}>
+      <ExamsListClient />
+    </Suspense>
+  );
+}