添加管理员逻辑

miniprogram/pages/admin/admin.wxml

@@ -2,7 +2,12 @@
 <view class="admin-container">
   <!-- 顶部导航栏 -->
   <view class="top-nav">
-    <text class="nav-title">配送管理系统</text>
+    <view class="header-left">
+      <view class="back-icon" bindtap="goBack">
+        <text class="back-arrow">‹</text>
+      </view>
+      <text class="nav-title">配送管理系统</text>
+    </view>
     <view class="user-info" wx:if="{{userInfo}}">
       <image class="user-avatar" src="/images/user-avatar.png" mode="aspectFill"></image>
       <text class="user-name">{{userInfo.name || '管理员'}}</text>