feat(AppWeightManage): 更新体重信息显示逻辑

- 在"最近称重时间"字段中，优先显示 todayCreateTime，若为空则显示 lastCreateTime
- 在"最新体重(公斤)"字段中，优先显示 todayWeight，若为空则显示 lastWeight

project/xumu/AppWeightManage/add.vue

@@ -102,7 +102,7 @@ export default {
             <b v-text="detail.variety"/>
           </el-form-item>
           <el-form-item label="最近称重时间">
-            <b v-text="detail.lastCreateTime"/>
+            <b v-text="detail.todayCreateTime||detail.lastCreateTime"/>
           </el-form-item>
           <el-form-item label="最新体重(公斤)">
             <b v-text="detail.todayWeight||detail.lastWeight"/>