feat(bottomnav): 根据 URL 参数 activityId 动态切换导航项

- 导入 useRoute 获取 URL 查询参数
- 将 navItems 从 shallowRef 改为 computed 实现动态更新
- 有 activityId 参数时显示"便民地图"
- 无 activityId 参数时显示"乐在重阳"
- 兼容不同活动场景的导航需求

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

 <!--
  * @Date: 2025-08-27 17:44:10
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2026-02-10 10:18:46
+ * @LastEditTime: 2026-02-10 11:03:56
  * @FilePath: /map-demo/src/components/BottomNav.vue
- * @Description: 文件描述
+ * @Description: 底部导航组件
 -->
 <template>
   <div v-if="isMiniProgramWebView" class="bottom-nav">
@@ -21,7 +21,8 @@
 </template>
 
 <script setup>
-import { computed, shallowRef } from 'vue';
+import { computed } from 'vue';
+import { useRoute } from 'vue-router';
 import wx from 'weixin-js-sdk'
 
 const homeIcon = 'https://cdn.ipadbiz.cn/lls_prog/icon/home.svg';
@@ -32,6 +33,7 @@ const activitiesIcon = 'https://cdn.ipadbiz.cn/lls_prog/icon/activities.svg';
 const activitiesIconActive = 'https://cdn.ipadbiz.cn/lls_prog/icon/activities_active1.svg';
 const meIcon = 'https://cdn.ipadbiz.cn/lls_prog/icon/me.svg';
 const meIconActive = 'https://cdn.ipadbiz.cn/lls_prog/icon/me_active1.svg';
+
 /**
  * 检测是否在小程序web-view环境中
  * @returns {boolean} 是否在小程序环境
@@ -40,14 +42,33 @@ const isMiniProgramWebView = computed(() => {
   return navigator.userAgent.includes('miniProgram');
 });
 
-const navItems = shallowRef([
+const route = useRoute();
+
+// 根据 URL 参数 activityId 动态生成导航项
+const navItems = computed(() => {
+  const hasActivityId = route.query.activityId;
+
+  const baseNavItems = [
     { path: '/pages/Dashboard/index', icon: homeIcon, activeIcon: homeIconActive, label: '首页' },
-  { path: '/pages/CheckinMap/index', icon: activitiesIcon, activeIcon: activitiesIconActive, label: '便民地图' },
     // { path: '/pages/RewardCategories/index', icon: rewardsIcon, activeIcon: rewardsIconActive, label: '兑换' },
     // TAG: 暂时写死以后可能会改变
     { path: '/pages/Rewards/index?id=health&category=health', icon: rewardsIcon, activeIcon: rewardsIconActive, label: '兑换' },
     { path: '/pages/Profile/index', icon: meIcon, activeIcon: meIconActive, label: '我的' },
-]);
+  ];
+
+  // 根据是否有 activityId 插入不同的第二个导航项
+  const activitiesItem = hasActivityId
+    ? { path: '/pages/CheckinMap/index', icon: activitiesIcon, activeIcon: activitiesIconActive, label: '便民地图' }
+    : { path: '/pages/ActivitiesCover/index', icon: activitiesIcon, activeIcon: activitiesIconActive, label: '乐在重阳' };
+
+  // 将活动相关项插入到首页和兑换之间
+  return [
+    baseNavItems[0], // 首页
+    activitiesItem,  // 活动/地图
+    baseNavItems[1], // 兑换
+    baseNavItems[2], // 我的
+  ];
+});
 
 const currentPage = computed(() => {
   // const pages = Taro.getCurrentPages();