Add 卓米会 mini program and admin server.

Initial commit of the WeChat mini program, Express backend, and admin console.

Co-authored-by: Cursor <cursoragent@cursor.com>

miniprogram/pages/detail/detail.wxml

@@ -0,0 +1,12 @@
+<activity-board
+  wx:if="{{activity}}"
+  activity="{{activity}}"
+  show-past="{{false}}"
+  bind:map="openMap"
+  bind:signup="goSignup"
+/>
+<view wx:elif="{{failed}}" class="empty">
+  <text>活动不存在或已下线</text>
+  <view class="home" bindtap="goHome">回到首页</view>
+</view>
+<view wx:else class="empty">加载中</view>