feat: add password change, trial subscription, batch import, UX improvements

Server:
- POST /api/v1/admin/password: admin password change with bcrypt migration
- POST /api/v1/subscription/trial: user trial activation, one per user
- POST /api/v1/admin/devices/batch: bulk device import (up to 500)
- Add trial plan (7 days, free) to PLANS constant

Admin console:
- Settings page: add password change form with validation
- Device page: add batch import modal with textarea input

Miniprogram:
- Treating page: add back button with stop-treatment confirmation
- Index page: add mock device bind button (dev mode only)

miniprogram/pages/index/index.js

@@ -1,5 +1,6 @@
 var ble = require('../../services/ble')
 var http = require('../../utils/request')
+var config = require('../../config/env')
 var app = getApp()
 
 Page({
@@ -12,10 +13,12 @@ Page({
     modeState: '空闲',
     bleState: 'disconnected',
     hasDevice: false,
-    deviceInfo: null
+    deviceInfo: null,
+    devMode: false
   },
 
   onShow: function () {
+    this.setData({ devMode: config.__DEV__ || false })
     this.checkState()
     this._onStatus = this.onBleStatus.bind(this)
     ble.on('status', this._onStatus)
@@ -145,6 +148,30 @@ Page({
     wx.navigateTo({ url: '/pages/wear-check/wear-check' })
   },
 
+  onMockBind: function () {
+    var self = this
+    var mockDeviceId = 'MOCK_' + Date.now().toString(36).toUpperCase()
+    wx.showModal({
+      title: '模拟绑定',
+      content: '将创建一个模拟设备 ' + mockDeviceId + ' 并绑定到当前账号',
+      success: function (res) {
+        if (res.confirm) {
+          http.post('/api/v1/device/bind', { device_id: mockDeviceId }).then(function (data) {
+            return http.post('/api/v1/device/bind/confirm', {
+              device_id: data.device_id,
+              bind_token: data.bind_token
+            })
+          }).then(function () {
+            wx.showToast({ title: '模拟绑定成功', icon: 'success' })
+            self.checkState()
+          }).catch(function (err) {
+            wx.showToast({ title: err.message || '绑定失败', icon: 'none' })
+          })
+        }
+      }
+    })
+  },
+
   onViewSubscription: function () {
     if (!this.data.subscription || this.data.subscription.status !== 'active') {
       wx.navigateTo({ url: '/pages/subscribe-plans/subscribe-plans' })

miniprogram/pages/index/index.wxml

@@ -4,6 +4,10 @@
       <text class="empty-icon">📱</text>
       <view class="empty-text">还没有绑定设备</view>
       <button class="btn-primary mt-30" bindtap="onAddDevice">扫码添加设备</button>
+      <view class="debug-actions" wx:if="{{devMode}}">
+        <view class="debug-label">🔧 调试工具</view>
+        <button class="btn-secondary btn-sm" bindtap="onMockBind">模拟绑定设备</button>
+      </view>
     </view>
   </view>