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>

server/server.js

@@ -0,0 +1,14 @@
+const app = require('./app')
+const db = require('./lib/db')
+
+const PORT = Number(process.env.PORT) || 3000
+
+db.read()
+
+app.listen(PORT, () => {
+  console.log(`卓米会服务已启动 http://localhost:${PORT}`)
+  console.log(`管理后台 http://localhost:${PORT}/admin`)
+  if (!process.env.WX_APPID || !process.env.WX_SECRET) {
+    console.log('未配置 WX_APPID / WX_SECRET，小程序登录走演示模式')
+  }
+})