fix: replace facial/medical terms with neutral position labels

Region names: 左脸→左区, 右脸→右区, 额头→上区, 下巴→下区,
鼻唇→中区, 左眼→左上区, 右眼→右上区, 全脸→全区域.
Replace 面部/面罩 with 设备 in wear-check and auto-scan pages.

miniprogram/pages/auto-scan/auto-scan.wxml

@@ -2,11 +2,11 @@
   <view class="page-header page-header-pink" style="padding-top: {{statusBarHeight + 24}}px;">
     <view class="nav-back" bindtap="onBack">‹ 返回</view>
     <view class="page-header-title">自动扫描</view>
-    <view class="page-header-subtitle">正在识别面部...</view>
+    <view class="page-header-subtitle">正在识别区域...</view>
   </view>
 
   <view class="page-content">
-    <view class="page-title">自动扫描面部区域</view>
+    <view class="page-title">自动扫描区域</view>
 
     <view class="scan-container">
       <view class="face-outline">
@@ -14,7 +14,7 @@
       </view>
     </view>
 
-    <view class="scan-hint">请将面罩对准面部</view>
+    <view class="scan-hint">请正确佩戴设备</view>
     <view class="scan-hint" style="font-size:24rpx;color:#999;margin-top:8rpx;">连接设备后可获取检测数据</view>
 
     <view class="scan-progress" wx:if="{{scanning}}">