feat(mp): Phase 1 测试覆盖 + UX 无障碍 — 106 tests PASS + ARIA + focus ring

测试:
- secure-storage: 26 tests (AES 加解密/明文 fallback/迁移/Base64 边界)
- request.ts: 16 tests (扩展 ResponseCache/patientId 隔离/requestUnlimited)
- mock-api: 修复 getCachedPatientId 缺失导致 health 测试失败

UX 无障碍 (10 组件):
- SegmentTabs/DoctorTabBar: role=tablist/tab + aria-selected
- PrimaryButton/SecondaryButton: role=button + aria-disabled/aria-busy
- Loading/LoadingCard: role=status + aria-live=polite
- EmptyState: role=status + aria-live=polite
- ErrorState: role=alert + aria-live=assertive
- TrendChart tooltip: role=tooltip + aria-live=polite
- FormInput: aria-invalid + aria-label

焦点管理:
- 新增 _focus-ring.scss mixin (focus + focus-visible)
- 5 组件 SCSS 应用 focus-ring

apps/miniprogram/__tests__/services/request.test.ts

@@ -23,7 +23,7 @@ vi.mock('@/utils/secure-storage', () => ({
 }));
 
 import Taro from '@tarojs/taro';
-import { api, clearRequestCache, resetForTesting } from '@/services/request';
+import { api, clearRequestCache, resetForTesting, setCachedPatientId } from '@/services/request';
 
 describe('request module', () => {
   beforeEach(() => {
@@ -148,4 +148,61 @@ describe('request module', () => {
       await expect(api.get('/bad-params')).rejects.toThrow('参数错误');
     });
   });
+
+  describe('ResponseCache', () => {
+    it('should cache GET responses and return cached on second call', async () => {
+      vi.mocked(Taro.request).mockResolvedValue({ statusCode: 200, data: { success: true, data: { id: '1' } } } as any);
+
+      await api.get('/cached-test');
+      await api.get('/cached-test');
+
+      expect(Taro.request).toHaveBeenCalledTimes(1);
+    });
+
+    it('should not cache POST requests', async () => {
+      vi.mocked(Taro.request).mockResolvedValue({ statusCode: 200, data: { success: true, data: {} } } as any);
+
+      await api.post('/no-cache', { a: 1 });
+      await api.post('/no-cache', { a: 1 });
+
+      expect(Taro.request).toHaveBeenCalledTimes(2);
+    });
+
+    it('clearRequestCache should clear cached entries', async () => {
+      vi.mocked(Taro.request).mockResolvedValue({ statusCode: 200, data: { success: true, data: { v: 1 } } } as any);
+
+      await api.get('/clear-test');
+      clearRequestCache();
+      await api.get('/clear-test');
+
+      expect(Taro.request).toHaveBeenCalledTimes(2);
+    });
+  });
+
+  describe('setCachedPatientId', () => {
+    it('should isolate cache entries by patient ID', async () => {
+      vi.mocked(Taro.request).mockResolvedValue({ statusCode: 200, data: { success: true, data: { v: 1 } } } as any);
+      setCachedPatientId('patient-A');
+      await api.get('/health/data');
+
+      setCachedPatientId('patient-B');
+      await api.get('/health/data');
+
+      // 不同 patient ID 应各自发请求（缓存隔离）
+      expect(Taro.request).toHaveBeenCalledTimes(2);
+    });
+  });
+
+  describe('requestUnlimited', () => {
+    it('should bypass concurrency limiter', async () => {
+      vi.mocked(Taro.request).mockResolvedValue({ statusCode: 200, data: { success: true, data: 'ok' } } as any);
+
+      const { requestUnlimited } = await import('@/services/request');
+      await requestUnlimited('GET', '/health/test');
+
+      expect(Taro.request).toHaveBeenCalledWith(
+        expect.objectContaining({ method: 'GET' }),
+      );
+    });
+  });
 });