fix: 补充缺失的Reading/Opportunity图标导入

frontend/src/layouts/MainLayout.vue

@@ -48,7 +48,7 @@ import { useRoute, useRouter } from 'vue-router'
 import {
   User, Monitor, Document, TrendCharts, WarningFilled, Connection,
   Menu, Bell, Setting, Coin, DataAnalysis, Money, DataLine,
-  DataBoard, Tools, Collection, Edit,
+  DataBoard, Tools, Collection, Edit, Reading, Opportunity,
 } from '@element-plus/icons-vue'
 import { MENU_ITEMS, ROLE_LABELS } from '../permission'
 
@@ -61,7 +61,7 @@ const mobileMenuOpen = ref(false)
 const iconMap: Record<string, any> = {
   Monitor, Document, TrendCharts, WarningFilled, Connection,
   User, Bell, Setting, Coin, DataAnalysis, Money, DataLine,
-  DataBoard, Collection, Edit,
+  DataBoard, Collection, Edit, Reading, Opportunity,
 }
 
 // 分组图标映射 — PDCA五组