refactor: restructure entire project for human maintainability

Server:
- Add Express framework, replace custom router/request parser
- Create DAO layer (12 files) centralizing all 73 SQL queries
- Rewrite 7 route files as thin Express controllers calling DAOs
- Add SCF-to-Express adapter (lib/serverless.js)
- Add auth middleware (middleware/auth.js)
- Remove dead code from lib/auth.js

Admin console:
- Extract DataTable component (table + pagination)
- Extract ConfirmModal component (modal + form styles)
- Create listMixin for paginated list pages
- Move form styles to common.css for slot compatibility
- Refactor device + subscription pages as examples

Miniprogram:
- Split 734-line BLE monolith into 4 focused modules
  (protocol, connection, commands, barrel index)
- Create API module (utils/api.js) with named functions
- Create page utilities (utils/page.js)
- Refactor index + profile pages to use API module

miniprogram/utils/api.js

@@ -0,0 +1,32 @@
+var http = require('./request')
+
+module.exports = {
+  // Auth
+  login: function (code) { return http.post('/api/v1/auth/login', { code: code }) },
+  getPhone: function (code) { return http.post('/api/v1/user/phone', { code: code }) },
+
+  // User
+  getProfile: function () { return http.get('/api/v1/user/profile') },
+  updateProfile: function (data) { return http.put('/api/v1/user/profile', data) },
+
+  // Device
+  getDevices: function () { return http.get('/api/v1/device/list') },
+  bindDevice: function (deviceId) { return http.post('/api/v1/device/bind', { device_id: deviceId }) },
+  confirmBind: function (deviceId, token) { return http.post('/api/v1/device/bind/confirm', { device_id: deviceId, bind_token: token }) },
+  mockBind: function (deviceId) { return http.post('/api/v1/device/mock-bind', { device_id: deviceId }) },
+  unbindDevice: function (deviceId) { return http.post('/api/v1/device/unbind', { device_id: deviceId }) },
+
+  // Subscription
+  getSubscription: function () { return http.get('/api/v1/subscription') },
+  activateTrial: function () { return http.post('/api/v1/subscription/trial') },
+  purchase: function (plan) { return http.post('/api/v1/subscription/purchase', { plan: plan }) },
+
+  // Treatment
+  getRecords: function (params) { return http.get('/api/v1/treatment/history', params) },
+  syncTreatment: function (data) { return http.post('/api/v1/treatment/sync', data) },
+  getRecordDetail: function (id) { return http.get('/api/v1/treatment/' + id) },
+
+  // Device commands
+  getPendingCommands: function (deviceId) { return http.get('/api/v1/device/command/pending', { device_id: deviceId }) },
+  reportCommandResult: function (data) { return http.post('/api/v1/device/command/result', data) }
+}

miniprogram/utils/page.js

@@ -0,0 +1,25 @@
+var app = getApp()
+
+/** Get status bar height for custom navigation pages */
+function getStatusBarHeight() {
+  return app.globalData.statusBarHeight || 44
+}
+
+/** Standard back navigation with fallback */
+function navigateBack(fallbackUrl) {
+  wx.navigateBack({
+    fail: function () {
+      if (fallbackUrl) {
+        wx.reLaunch({ url: fallbackUrl })
+      }
+    }
+  })
+}
+
+/** Check if dev mode is enabled */
+function isDevMode() {
+  var config = require('../config/env')
+  return config.__DEV__ || false
+}
+
+module.exports = { getStatusBarHeight: getStatusBarHeight, navigateBack: navigateBack, isDevMode: isDevMode }