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/history/history.json

@@ -1,5 +1,5 @@
 {
-  "navigationBarTitleText": "护理记录",
+  "navigationBarTitleText": "使用记录",
   "navigationBarBackgroundColor": "#E6508C",
   "navigationBarTextStyle": "white",
   "enablePullDownRefresh": true

miniprogram/pages/history/history.wxml

@@ -25,7 +25,7 @@
 
     <view class="empty-state" wx:if="{{!loading && records.length === 0}}">
       <text class="empty-icon">📃</text>
-      <view class="empty-text">暂无护理记录</view>
+      <view class="empty-text">暂无使用记录</view>
     </view>
 
     <view class="loading-more" wx:if="{{loadingMore}}">加载更多...</view>