feat: 意见反馈功能

新增完整反馈闭环:
- 后端: Feedback 模块 (schema+service+controller+module)
  - POST /api/feedback (用户提交)
  - GET /api/feedback (管理员列表)
  - PATCH /api/feedback/:id/resolve (管理员标记已处理)
- 前端: pages/feedback/feedback.vue
  - 三种反馈类型: 问题反馈/改进建议/点赞鼓励
  - 文本输入 + 联系方式选填
  - 提交后显示成功提示
- 用户页新增'意见反馈'菜单入口
- 管理后台可通过 API 查看和管理反馈

zhiyin-app/src/pages.json

@@ -19,7 +19,8 @@
     { "path": "pages/privacy/privacy", "style": { "navigationBarTitleText": "隐私政策" } },
     { "path": "pages/share/share", "style": { "navigationBarTitleText": "我的分享" } },
     { "path": "pages/review/review", "style": { "navigationBarTitleText": "面试复盘分析" } },
-    { "path": "pages/career/career", "style": { "navigationBarTitleText": "AI择业顾问" } }
+    { "path": "pages/career/career", "style": { "navigationBarTitleText": "AI择业顾问" } },
+    { "path": "pages/feedback/feedback", "style": { "navigationBarTitleText": "意见反馈" } }
   ],
   "tabBar": {
     "color": "#999999",