fix: add wx:key to v-for loops in RecommendedFeed and parent-index to suppress WXML warnings

cfc-frontend/components/RecommendedFeed.vue

@@ -7,7 +7,7 @@
     <view class="feed-list">
       <!-- 无数据时显示占位 -->
       <template v-if="(!items || items.length === 0) && !loading">
-        <view class="feed-card feed-placeholder" v-for="i in 4" :key="'ph-' + i">
+        <view class="feed-card feed-placeholder" v-for="i in 4" :key="i">
           <view class="feed-img-placeholder"></view>
           <view class="feed-info">
             <text class="feed-title-placeholder line-clamp-2">精彩内容即将上线</text>

cfc-frontend/pages/index/parent-index.vue

@@ -258,7 +258,7 @@
           </view>
           <!-- 无数据时显示占位卡片 -->
           <template v-else-if="indexArticles.length === 0">
-            <view class="article-card" v-for="i in 3" :key="'ph-' + i">
+            <view class="article-card" v-for="i in 3" :key="i">
               <view class="article-category" :style="{ background: gradientColors[(i-1) % gradientColors.length] }">
                 <text class="article-category-text">推荐文章</text>
               </view>