refactor: migrate to WeChat cloud development

- 新增 cloud-functions/ 目录（6个云函数：auth/device/subscription/treatment/user/admin）
- 云函数使用 wx-server-sdk + 云数据库（不再依赖 MySQL）
- auth 云函数通过 cloud.getWXContext() 自动获取 openid，无需手动 wx.login
- request.js 改为通过 wx.cloud.callFunction() 调用云函数
- 登录流程简化：点击授权 → 直接调 auth 云函数 → 获取用户信息
- 保留 HTTP 模式切换能力（USE_CLOUD 变量控制）

miniprogram/cloud-functions/device/index.js

@@ -0,0 +1,89 @@
+const cloud = require('wx-server-sdk')
+cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
+const db = cloud.database()
+const _ = db.command
+
+exports.main = async (event, context) => {
+  const wxContext = cloud.getWXContext()
+  const openid = wxContext.OPENID
+  const { action } = event
+
+  if (action === 'bind') {
+    const { device_id } = event.data
+    if (!device_id) return { code: -1, message: '缺少设备ID' }
+
+    const existBind = await db.collection('bindings').where({ openid, status: 'active' }).count()
+    if (existBind.total > 0) {
+      const exist = await db.collection('bindings').where({ openid, status: 'active' }).get()
+      return { code: 2001, message: '已绑定设备', data: { device_id: exist.data[0].device_id } }
+    }
+
+    await db.collection('bindings').add({
+      data: {
+        openid,
+        device_id,
+        status: 'active',
+        bind_time: db.serverDate()
+      }
+    })
+
+    const subExist = await db.collection('subscriptions').where({ openid, status: 'active' }).count()
+    if (subExist.total === 0) {
+      await db.collection('subscriptions').add({
+        data: {
+          openid,
+          plan_type: 'trial',
+          status: 'active',
+          start_time: db.serverDate(),
+          end_time: new Date(Date.now() + 7 * 24 * 3600 * 1000),
+          remaining_days: 7
+        }
+      })
+    }
+
+    return {
+      code: 0,
+      data: {
+        device_id,
+        bind_token: 'bt_' + Date.now(),
+        subscription: { plan_type: 'trial', remaining_days: 7 }
+      }
+    }
+  }
+
+  if (action === 'unbind') {
+    await db.collection('bindings').where({ openid, status: 'active' }).update({ data: { status: 'inactive' } })
+    return { code: 0, data: {} }
+  }
+
+  if (action === 'list') {
+    const bindings = await db.collection('bindings').where({ openid, status: 'active' }).get()
+    const devices = bindings.data.map(b => ({
+      device_id: b.device_id,
+      name: '我的光面膜',
+      status: 'online',
+      bind_time: b.bind_time
+    }))
+    return { code: 0, data: { devices, total: devices.length } }
+  }
+
+  if (action === 'detail') {
+    const { device_id } = event.data
+    const bindings = await db.collection('bindings').where({ openid, device_id, status: 'active' }).get()
+    if (bindings.data.length === 0) return { code: -1, message: '设备未绑定' }
+    const b = bindings.data[0]
+    return {
+      code: 0,
+      data: {
+        device_id: b.device_id,
+        name: '我的光面膜',
+        firmware_version: '1.0.0',
+        battery_level: 85,
+        status: 'online',
+        bind_time: b.bind_time
+      }
+    }
+  }
+
+  return { code: -1, message: '未知操作' }
+}

miniprogram/cloud-functions/device/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "device",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "dependencies": {
+    "wx-server-sdk": "~2.6.3"
+  }
+}