feat(miniprogram): service 层测试框架搭建

- 新增 __tests__/helpers/: mock-taro (Taro API mock) + mock-api (request mock)
- 示例测试: patient.test.ts (3 用例) + appointment.test.ts (9 用例)
- 覆盖 list/create/update/cancel/calendar 等核心场景
- 全部 42 测试通过（含 4 个已有 BLE 测试）

apps/miniprogram/__tests__/helpers/index.ts

@@ -0,0 +1,2 @@
+export { mockTaro, createTaroMock } from './mock-taro';
+export { mockApi, apiOk } from './mock-api';