fix(my-registration): 修复信息展示不全问题

- 地址过长时显示省略号
- 空字段显示"暂无"

src/pages/my-registration/my-registration.vue

@@ -19,22 +19,22 @@
 
         <view class="event-info">
           <text class="label">地点：</text>
-          <text class="value">{{ item.location }}</text>
+          <text class="value location-text">{{ item.location || "暂无" }}</text>
         </view>
 
         <view class="event-info">
           <text class="label">比赛时间：</text>
-          <text class="value">{{ item.matchTime }}</text>
+          <text class="value">{{ item.matchTime || "暂无" }}</text>
         </view>
 
         <view class="event-info">
           <text class="label">报名项目：</text>
-          <text class="value">{{ item.projects }}</text>
+          <text class="value">{{ item.projects || "暂无" }}</text>
         </view>
 
         <view class="event-info">
           <text class="label">联系人：</text>
-          <text class="value">{{ item.contact }}</text>
+          <text class="value">{{ item.contact || "暂无" }}</text>
         </view>
 
         <view class="event-info">
@@ -396,6 +396,14 @@ export default {
   flex: 1;
 }
 
+.location-text {
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  display: block;
+  max-width: 480rpx;
+}
+
 .participants {
   word-break: break-all;
 }