fix(FEAT-QA-001): 隔离市场概览 E2E 测试时钟

server/apps/api/test/market-overview.e2e-spec.ts

@@ -1,7 +1,7 @@
 import type { INestApplication } from '@nestjs/common';
 import { Test } from '@nestjs/testing';
 import request from 'supertest';
-import { afterEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 
 import { MarketOverviewController } from '../src/market-overview/market-overview.controller';
 import {
@@ -12,9 +12,19 @@ import {
 describe('市场概览 HTTP API', () => {
   let app: INestApplication | undefined;
 
+  beforeEach(() => {
+    // 固定到夹具交易日，避免测试随自然日期变化把正确的 delayed 响应误判为失败。
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date('2026-08-18T03:00:00.000Z'));
+  });
+
   afterEach(async () => {
-    await app?.close();
-    app = undefined;
+    try {
+      await app?.close();
+    } finally {
+      app = undefined;
+      vi.useRealTimers();
+    }
   });
 
   it('按模块返回指数和 TDX 来源元数据', async () => {