refactor(P2/P3): 完成全部7批重构 — 模块化、SSE退避、无障碍、Zod校验、Server组件、Room关系化

批次A：重命名 + 路由拆分
- store.ts → roomRepository.ts，更新全部 import
- blindbox/plan/route.ts 精简为薄路由，业务逻辑抽取到 planActions.ts / planQueries.ts

批次B：blindboxPlanGen.ts 拆分（710行 → src/lib/plan/）
- agentPlan.ts：Agent 工具调用与系统提示
- legacyPlan.ts：非 Agent 备用生成逻辑
- ideaSelection.ts：Idea 筛选与 Slot 映射
- transitEnrichment.ts：交通信息查询与填充
- index.ts：runPlanGeneration 主入口

批次C：SSE 连接稳定性
- useRoomPolling.ts 加入指数退避重连（上限60s，含Jitter）
- plan/stream/route.ts 添加30s心跳 + abort信号清理

批次D：无障碍修复
- Modal：role=dialog、aria-modal、aria-labelledby
- AuthModal：aria-label关闭按钮、tablist/tab/aria-selected
- PlanItemEditModal、QrInviteModal：补全aria-label
- BlindboxPlan：图标按钮aria-label

批次E：Zod 引入
- src/lib/schemas/ai.ts：AI返回值 Schema（IdeaTagsSchema等5个）
- src/lib/schemas/requests.ts：请求体 Schema
- ai.ts 手工验证替换为 Zod safeParse

批次F：Server Components
- achievements/page.tsx → Server Component + AchievementsClient.tsx
- profile/page.tsx → Server Component + ProfileClient.tsx

批次G：Room 关系化模型
- prisma/schema.prisma：新增 RoomMember、RoomRestaurant、RoomLike、RoomSwipe 4张表
- migration：20260302010000_room_relational_model
- roomRepository.ts 完整重写（关系查询+应用锁）
- buildRoomStatus.ts 适配关系查询

测试：全部329个用例通过，修复68个因auth mock缺失导致的测试失败

src/app/api/user/achievements/route.test.ts

@@ -2,17 +2,25 @@ import { describe, it, expect, vi, beforeEach } from "vitest";
 import { prismaMock, resetPrismaMock } from "@/__tests__/helpers/prisma-mock";
 import { createRequest, parseJsonResponse } from "@/__tests__/helpers/api-test-utils";
 import { TEST_RESTAURANT } from "@/__tests__/helpers/fixtures";
+import { ApiError } from "@/lib/api";
+
+vi.mock("@/lib/auth", () => ({
+  getAuthUserId: vi.fn().mockResolvedValue("user-1"),
+}));
 
 import { GET } from "./route";
+import { getAuthUserId } from "@/lib/auth";
 
 const mockCtx = { params: Promise.resolve({}) };
 
 beforeEach(() => {
   resetPrismaMock();
+  vi.mocked(getAuthUserId).mockResolvedValue("user-1");
 });
 
 describe("GET /api/user/achievements", () => {
-  it("returns 401 when no userId", async () => {
+  it("returns 401 when not authenticated", async () => {
+    vi.mocked(getAuthUserId).mockRejectedValueOnce(new ApiError("请先登录", 401));
     const req = createRequest("/api/user/achievements");
     const res = await GET(req, mockCtx);
     expect(res.status).toBe(401);
@@ -48,7 +56,7 @@ describe("GET /api/user/achievements", () => {
       { id: "bb-room-1", name: "周末", code: "ABC123" },
     ] as never);
 
-    const req = createRequest("/api/user/achievements?userId=user-1");
+    const req = createRequest("/api/user/achievements");
     const res = await GET(req, mockCtx);
     const { status, data } = await parseJsonResponse(res);