fix: 修改图片显示模式为scaleToFill以适配不同尺寸

将ActivitiesCover和AdPage页面的图片显示模式从aspectFill改为scaleToFill，确保图片在不同尺寸设备上都能完整显示

 <!--
  * @Date: 2022-09-19 14:11:06
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-09-19 17:28:31
+ * @LastEditTime: 2025-09-19 20:20:21
  * @FilePath: /lls_program/src/pages/ActivitiesCover/index.vue
  * @Description: 活动海报页面 - 展示活动信息并处理定位授权
 -->
@@ -11,7 +11,7 @@
     <image
       :src="defaultPoster"
       class="background-image"
-      mode="aspectFill"
+      mode="scaleToFill"
     />
 
     <!-- 分享按钮组件 -->

 <!--
  * @Date: 2022-09-19 14:11:06
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-09-19 13:48:33
+ * @LastEditTime: 2025-09-19 20:19:12
  * @FilePath: /lls_program/src/pages/AdPage/index.vue
  * @Description: 广告页面
 -->
@@ -11,13 +11,13 @@
     <image
       :src="adImageUrl"
       class="ad-background"
-      mode="aspectFill"
+      mode="scaleToFill"
       @tap="handleImageClick"
     />
 
     <!-- 右上角分享按钮 -->
     <view class="share-button-container" @tap.stop>
-      <button 
+      <button
         class="share-button"
         open-type="share"
       >