fix(health): 更新体重显示逻辑

- 将默认体重值从 "80.0 公斤" 更改为 "--"
- 确保在没有数据时正确显示占位符

src/pages/public/health/index.vue

@@ -12,7 +12,7 @@
         <view class="menu-item" @click="openDetail('physical','weight')">
           <image src="/static/icons/remixicon/weight.svg" class="menu-icon" mode="widthFix" />
           <text class="menu-text">体重</text>
-          <text class="menu-value">80.0 公斤</text>
+          <text class="menu-value">--</text>
           <uni-icons class="menu-arrow" type="arrowright" size="20" color="#c0c0c0" />
         </view>
         <view class="menu-item" @click="openDetail('physical','bmi')">