fix(portal): 修复微官网在浏览器打开时的跨域与网络解析报错，支持默认名片平滑降级

backend/test/modules/card/portal-default-fallback.test.ts

@@ -0,0 +1,67 @@
+import { CardPortalService } from '../../../src/modules/card/service/portal';
+import { CardInfoEntity } from '../../../src/modules/card/entity/info';
+import { CardBentoEntity } from '../../../src/modules/card/entity/bento';
+
+describe('CardPortalService: default 标识平滑降级与微官网访问容错 (TDD Red -> Green)', () => {
+  let cardPortalService: CardPortalService;
+
+  const mockCardData: CardInfoEntity[] = [
+    {
+      id: 1,
+      slug: 'alex-morgan',
+      name: 'Alex Morgan',
+      title: 'VP of Global Business',
+      company: 'OmniCard AI Global Inc.',
+      status: 'published',
+      createTime: new Date(),
+      updateTime: new Date(),
+    } as CardInfoEntity,
+  ];
+
+  beforeEach(() => {
+    cardPortalService = new CardPortalService();
+    (CardPortalService as any).localCache?.clear?.();
+
+    const mockCardRepo = {
+      findOne: jest.fn(async (options: any) => {
+        const where = options?.where;
+        // 如果是按默认/第一张已发布排序查询
+        if (options?.order?.id === 'ASC' && where?.status === 'published') {
+          return mockCardData.find((c) => c.status === 'published') || null;
+        }
+        if (Array.isArray(where)) {
+          return mockCardData.find((c) => c.id === where[0]?.id || c.slug === where[1]?.slug) || null;
+        }
+        if (where?.slug) {
+          return mockCardData.find((c) => c.slug === where.slug) || null;
+        }
+        if (where?.id) {
+          return mockCardData.find((c) => c.id === where.id) || null;
+        }
+        return null;
+      }),
+    };
+
+    const mockBentoRepo = {
+      find: jest.fn(async () => []),
+    };
+
+    cardPortalService.cardInfoEntity = mockCardRepo as any;
+    cardPortalService.cardBentoEntity = mockBentoRepo as any;
+  });
+
+  it('1. 当请求 slug 为 default 且无 default 名片时，应自动平滑降级获取首张已发布名片', async () => {
+    const res = await cardPortalService.getPortalDetail('default');
+    expect(res).toBeDefined();
+    expect(res.name).toBe('Alex Morgan');
+    expect(res.slug).toBe('alex-morgan');
+    expect(res.status).toBe('published');
+  });
+
+  it('2. 当请求明确的 slug 时，应正常返回指定名片', async () => {
+    const res = await cardPortalService.getPortalDetail('alex-morgan');
+    expect(res).toBeDefined();
+    expect(res.name).toBe('Alex Morgan');
+    expect(res.slug).toBe('alex-morgan');
+  });
+});