补充 VP 模块注册 + 前端 API 封装

- app.module.ts: 注册 VirtualPaymentModule
- config.ts + api.ts: 添加虚拟支付 API 端点
- useGravityPurchase.ts: VP 购买逻辑
- interview.vue / user.vue: 适配 VP 调用
- admin.controller.ts: 管理端虚拟支付相关调整
- payment.controller.spec.ts: 测试适配

zhiyin-app/src/services/api.ts

@@ -105,6 +105,12 @@ const apiService = {
       request(API_ENDPOINTS.CAREER.CHAT, 'POST', { message, history }, true),
     positions: () => request(API_ENDPOINTS.CAREER.POSITIONS, 'GET', undefined, true),
   },
+  virtualPayment: {
+    create: (data: { type: string; quantity: number; wxCode: string }) =>
+      request(API_ENDPOINTS.VIRTUAL_PAYMENT.CREATE, 'POST', data, true),
+    check: (outTradeNo: string) =>
+      request(API_ENDPOINTS.VIRTUAL_PAYMENT.CHECK(outTradeNo), 'GET', undefined, true),
+  },
 }
 
 export default apiService