feat: 添加小程序跳转支持并重构底部导航栏

- 新增 miniProgram.js 工具模块，提供 H5 环境下检测微信小程序 webview 及页面跳转能力
- 重构 AppTabbar 组件，替换 NutUI Tabbar 为自定义实现，优化视觉样式
- 在 H5 环境下优先尝试使用小程序桥接跳转页面，增强多端体验一致性

 <template>
   <view class="app-tabbar">
-    <nut-tabbar
-      :model-value="activeTab"
-      bottom
-      placeholder
-      safe-area-inset-bottom
-      :active-color="activeColor"
-      :unactive-color="inactiveColor"
-      @tab-switch="handleTabSwitch"
-    >
-      <nut-tabbar-item
+    <view class="app-tabbar__placeholder" />
+
+    <view class="app-tabbar__wrap">
+      <view class="app-tabbar__panel">
+        <view
           v-for="item in tabItems"
           :key="item.name"
-        :name="item.name"
-        :tab-title="item.title"
+          class="app-tabbar__item"
+          :class="{ 'is-active': isActive(item.name) }"
+          @tap="handleTabClick(item)"
         >
-        <template #icon="{ active }">
+          <view class="app-tabbar__item-inner">
+            <view class="app-tabbar__icon">
               <component
                 :is="item.icon"
                 size="18"
-            :color="active ? activeColor : inactiveColor"
+                :color="isActive(item.name) ? activeColor : inactiveColor"
               />
-        </template>
-      </nut-tabbar-item>
-    </nut-tabbar>
+            </view>
+            <text class="app-tabbar__label">{{ item.title }}</text>
+          </view>
+        </view>
+      </view>
+    </view>
   </view>
 </template>
 
 <script setup>
-import { computed } from 'vue'
 import Taro from '@tarojs/taro'
 import { Home, Message, My } from '@nutui/icons-vue-taro'
+// 迁移到独立 H5 项目时，别忘了把 miniProgram helper 一起带走。
+import { isH5Env, navigateToMiniProgramPage } from '@/utils/miniProgram'
 
 const props = defineProps({
   current: {
@@ -63,44 +64,88 @@ const tabItems = [
   },
 ]
 
-const activeTab = computed(() => props.current)
+const isActive = (name) => name === props.current
 
-const handleTabSwitch = (...args) => {
-  const nextTab = args[1]
-  const target = tabItems.find((item) => item.name === nextTab)
+const handleTabClick = async (item) => {
+  if (!item?.url || item.name === props.current) {
+    return
+  }
 
-  if (!target || target.name === props.current) {
+  if (isH5Env()) {
+    try {
+      const has_navigated = await navigateToMiniProgramPage(item.url)
+
+      if (has_navigated) {
         return
       }
+    } catch (error) {
+      console.error('H5 跳转小程序页面失败:', error)
+    }
+  }
 
-  Taro.redirectTo({
-    url: target.url,
-  })
+  Taro.redirectTo({ url: item.url })
 }
 </script>
 
 <style lang="less">
 .app-tabbar {
-  :deep(.nut-tabbar) {
-    left: 24rpx;
-    right: 24rpx;
-    bottom: 24rpx;
-    width: auto;
-    border: 2rpx solid rgba(166, 121, 57, 0.12);
-    border-radius: 999rpx;
-    background: rgba(255, 255, 255, 0.96);
-    box-shadow: 0 24rpx 60rpx rgba(15, 23, 42, 0.12);
-    overflow: hidden;
+  .app-tabbar__placeholder {
+    height: 132rpx;
+    flex-shrink: 0;
+  }
+
+  .app-tabbar__wrap {
+    position: fixed;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    z-index: 100;
+    box-sizing: border-box;
   }
 
-  :deep(.nut-tabbar-item_icon-box) {
-    padding-top: 8rpx;
+  .app-tabbar__panel {
+    display: flex;
+    align-items: stretch;
+    min-height: 132rpx;
+    padding: 16rpx 24rpx;
+    border-top: 2rpx solid rgba(166, 121, 57, 0.12);
+    background: rgba(255, 255, 255, 0.98);
+    box-sizing: border-box;
+    backdrop-filter: blur(12rpx);
   }
 
-  :deep(.nut-tabbar-item_icon-box_nav-word) {
-    margin-top: 8rpx;
+  .app-tabbar__item {
+    flex: 1;
+    min-width: 0;
+  }
+
+  .app-tabbar__item-inner {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    gap: 10rpx;
+    min-height: 100rpx;
+    border-radius: 20rpx;
+    color: #8b95a7;
+    transition: background-color 0.2s ease, color 0.2s ease, transform 0.2s ease;
+  }
+
+  .app-tabbar__icon {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    line-height: 1;
+  }
+
+  .app-tabbar__label {
     font-size: 22rpx;
     font-weight: 600;
+    line-height: 1.2;
+  }
+
+  .app-tabbar__item.is-active .app-tabbar__item-inner {
+    color: #a67939;
   }
 }
 </style>

+const WECHAT_JS_SDK_URL = 'https://res.wx.qq.com/open/js/jweixin-1.6.0.js'
+
+let wechat_bridge_loading_promise = null
+
+const isBrowserEnv = () => typeof window !== 'undefined' && typeof document !== 'undefined'
+
+const getWechatBridge = () => {
+  if (typeof window === 'undefined') {
+    return null
+  }
+
+  return window.wx || window.jWeixin || null
+}
+
+const getMiniProgramBridge = () => getWechatBridge()?.miniProgram || null
+
+export const isH5Env = () => isBrowserEnv()
+
+const ensureWechatBridge = async () => {
+  if (!isH5Env()) {
+    return null
+  }
+
+  const current_bridge = getWechatBridge()
+
+  if (current_bridge) {
+    return current_bridge
+  }
+
+  if (!wechat_bridge_loading_promise) {
+    wechat_bridge_loading_promise = new Promise((resolve, reject) => {
+      const script = document.createElement('script')
+
+      script.src = WECHAT_JS_SDK_URL
+      script.async = true
+      script.onload = () => resolve(getWechatBridge())
+      script.onerror = () => reject(new Error('微信 JS SDK 加载失败'))
+
+      document.head.appendChild(script)
+    })
+  }
+
+  try {
+    return await wechat_bridge_loading_promise
+  } catch (error) {
+    wechat_bridge_loading_promise = null
+    throw error
+  }
+}
+
+export const isWechatMiniProgramWebview = () => new Promise((resolve) => {
+  const check_env = async () => {
+    if (!isH5Env()) {
+      resolve(false)
+      return
+    }
+
+    try {
+      await ensureWechatBridge()
+    } catch (error) {
+      console.error('微信 JS SDK 初始化失败:', error)
+      resolve(false)
+      return
+    }
+
+    const mini_program_bridge = getMiniProgramBridge()
+
+    if (!mini_program_bridge) {
+      resolve(false)
+      return
+    }
+
+    if (typeof mini_program_bridge.getEnv !== 'function') {
+      resolve(true)
+      return
+    }
+
+    mini_program_bridge.getEnv((result = {}) => {
+      resolve(!!result.miniprogram)
+    })
+  }
+
+  check_env().catch(() => {
+    resolve(false)
+  })
+})
+
+export const navigateToMiniProgramPage = async (url = '') => {
+  const normalized_url = String(url || '').trim()
+
+  if (!normalized_url) {
+    return false
+  }
+
+  const is_supported_webview = await isWechatMiniProgramWebview()
+
+  if (!is_supported_webview) {
+    return false
+  }
+
+  const mini_program_bridge = getMiniProgramBridge()
+
+  if (typeof mini_program_bridge?.navigateTo !== 'function') {
+    return false
+  }
+
+  return new Promise((resolve, reject) => {
+    mini_program_bridge.navigateTo({
+      url: normalized_url,
+      success: () => resolve(true),
+      fail: (error) => reject(error),
+    })
+  })
+}