fix(front): 修复前台退出登录确认弹窗样式丢失

更新说明：\n1. 在用户端 AppLayout 显式引入 Element Plus 的 Message/MessageBox 样式。\n2. 修复退出登录确认弹窗偶发样式异常（看起来像 JS 未加载）的显示问题。\n3. 同步更新前台构建产物与 manifest。

app-frontend/src/layouts/AppLayout.vue

@@ -3,6 +3,8 @@ import { computed, onBeforeUnmount, onMounted, reactive, ref } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 import { ElMessage, ElMessageBox } from 'element-plus'
 import { Calendar, Camera, User } from '@element-plus/icons-vue'
+import 'element-plus/es/components/message/style/css'
+import 'element-plus/es/components/message-box/style/css'
 
 import { fetchActiveAnnouncement, dismissAnnouncement } from '../api/announcements'
 import { fetchMyFeedbacks, submitFeedback } from '../api/feedback'