feat(i18n): 剩余15页全量接入中英(登录/注册/扫码/绑定/佩戴/扫描/治疗/订阅/帮助等)

- 3 个并行 agent 各管 5 页,互不重叠命名空间
- 全 App 18 页均 i18n.bind,22 命名空间/400 键中英对齐
- 动态文案(时长/天数/价格/区域)JS 内 i18n.t 计算;区域标签复用 common.regions

miniprogram/pages/help/help.wxml

@@ -1,13 +1,13 @@
 <view class="page">
   <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">使用帮助</view>
+    <view class="nav-back" bindtap="onBack">‹ {{i18n.common.back}}</view>
+    <view class="page-header-title">{{i18n.help.title}}</view>
   </view>
   <view class="page-content">
     <view class="placeholder-container">
       <view class="placeholder-icon">📖</view>
-      <view class="placeholder-text">内容建设中</view>
-      <view class="placeholder-sub">帮助文档正在编写，敬请期待</view>
+      <view class="placeholder-text">{{i18n.help.placeholderText}}</view>
+      <view class="placeholder-sub">{{i18n.help.placeholderSub}}</view>
     </view>
   </view>
 </view>