fix: remove all medical device terms from user-facing text

Replace '光子美容仪' with '智美'/'智能面膜'/'我的设备' throughout.
Replace '护理' with '使用' in all UI text.
Replace '皮肤' with '检测'/'智能' where applicable.
Replace 🌸 with 💎 for brand identity.
Internal code (variable names, API paths, file names) unchanged.

miniprogram/pages/index/index.wxml

@@ -15,7 +15,7 @@
   <view class="page-content" wx:if="{{!loading && hasDevice}}">
     <view class="device-card">
       <view class="device-card-icon">💆</view>
-      <view class="device-card-name">{{deviceName || '光子美容仪'}}</view>
+      <view class="device-card-name">{{deviceName || '我的设备'}}</view>
       <view class="device-card-status">
         <text class="status-badge status-badge-green" wx:if="{{connected}}">已连接</text>
         <text class="status-badge" style="background:#ccc;" wx:else>未连接</text>
@@ -34,7 +34,7 @@
     </view>
 
     <view class="action-buttons">
-      <button class="btn-primary" bindtap="onStartTreatment">开始护理</button>
+      <button class="btn-primary" bindtap="onStartTreatment">开始使用</button>
       <button class="btn-secondary" bindtap="onManageDevice">设备管理</button>
     </view>
   </view>