修复 H5 嵌入小程序导航栏冲突

- 识别微信小程序 web-view 宿主环境
- 宿主导航存在时隐藏 H5 自绘返回与页面标题
- 收回详情、搜索、讲解列表页面顶部预留空间

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/pages/search/index.vue

@@ -1,6 +1,6 @@
 <template>
-  <view class="poi-search-page">
-    <view class="search-header">
+  <view class="poi-search-page" :class="{ 'host-navigation': shouldUseHostNavigation }">
+    <view v-if="!shouldUseHostNavigation" class="search-header">
       <view class="search-header-copy">
         <text class="page-title">点位搜索</text>
         <text class="page-subtitle">Search Museum Locations</text>
@@ -21,11 +21,13 @@
 </template>
 
 <script setup lang="ts">
-import { onMounted, onUnmounted, ref } from 'vue'
+import { computed, onMounted, onUnmounted, ref } from 'vue'
 import { onLoad } from '@dcloudio/uni-app'
 import PoiSearchPanel from '@/components/search/PoiSearchPanel.vue'
+import { isEmbeddedInWechatMiniProgram } from '@/utils/hostEnvironment'
 
 const initialKeyword = ref('')
+const shouldUseHostNavigation = computed(() => isEmbeddedInWechatMiniProgram())
 
 onLoad((options: any) => {
   const keyword = typeof options.keyword === 'string'
@@ -119,6 +121,14 @@ onUnmounted(() => {
 }
 /* #endif */
 
+.poi-search-page.host-navigation {
+  padding-top: 0;
+}
+
+.poi-search-page.host-navigation::before {
+  display: none;
+}
+
 .search-header {
   position: relative;
   z-index: 1;