feat: support indefinite borrow period for long-term asset allocation

inventory-web/src/views/transaction/records.vue

@@ -46,6 +46,9 @@
             <el-tag type="success" size="small">实际</el-tag>
             {{ row.return_time || '-' }}
           </div>
+          <div v-else-if="!row.expected_return_time">
+            <el-tag type="primary" size="small">无限期</el-tag>
+          </div>
           <div v-else>
             <el-tag type="info" size="small">预计</el-tag>
             {{ formatExpectedTime(row.expected_return_time).text }}
@@ -163,7 +166,7 @@ const handlePage = (val: number) => {
 
 // ★ 新增：格式化预计归还时间及倒计时逻辑
 const formatExpectedTime = (timeStr: string) => {
-  if (!timeStr) return { text: '-', diffText: '', cssClass: '' }
+  if (!timeStr) return { text: '无限期', diffText: '', cssClass: '' }
 
   // 后端返回的可能是 YYYY-MM-DD HH:mm:ss，我们只取日期部分比较
   const expected = dayjs(timeStr).startOf('day')