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/services/ble/index.js

@@ -0,0 +1,59 @@
+// BLE service barrel — re-exports a unified API
+// Usage: var ble = require('../../services/ble')
+
+var protocol = require('./protocol')
+var connection = require('./connection')
+var commands = require('./commands')
+
+module.exports = {
+  // Constants
+  SERVICE: protocol.SERVICE,
+  CHAR: protocol.CHAR,
+  CMD: protocol.CMD,
+  NOTIFY: protocol.NOTIFY,
+  MODE_STATE: protocol.MODE_STATE,
+  WAVELENGTH: protocol.WAVELENGTH,
+  TREAT_MODE: protocol.TREAT_MODE,
+  REGION: protocol.REGION,
+  DEVICE_ERR: protocol.DEVICE_ERR,
+
+  // Connection
+  isConnected: connection.isConnected,
+  getDeviceId: connection.getDeviceId,
+  startScan: connection.startScan,
+  stopScan: connection.stopScan,
+  connect: connection.connect,
+  disconnect: connection.disconnect,
+  setAutoReconnect: connection.setAutoReconnect,
+  on: connection.on,
+  off: connection.off,
+
+  // Commands
+  readDeviceInfo: commands.readDeviceInfo,
+  setParams: commands.setParams,
+  startTreatment: commands.startTreatment,
+  stopTreatment: commands.stopTreatment,
+  queryStatus: commands.queryStatus,
+  bindDevice: commands.bindDevice,
+  unbindDevice: commands.unbindDevice,
+
+  // Protocol utilities
+  buildFrame: protocol.buildFrame,
+  parseFrame: protocol.parseFrame,
+  parseStatusReport: protocol.parseStatusReport,
+  parseAck: protocol.parseAck,
+  parseTreatmentComplete: protocol.parseTreatmentComplete,
+  parseException: protocol.parseException,
+
+  // Display helpers
+  REGION_NAMES: protocol.REGION_NAMES,
+  getRegionName: protocol.getRegionName,
+  getWavelengthName: protocol.getWavelengthName,
+  getModeStateName: protocol.getModeStateName,
+
+  // Byte utilities
+  bufferToBytes: protocol.bufferToBytes,
+  bytesToBuffer: protocol.bytesToBuffer,
+  hexToBytes: protocol.hexToBytes,
+  bytesToHex: protocol.bytesToHex
+}