fix: 修复股票搜索下拉不显示问题，增加activeSearchIndex赋值

pages/config/config.vue

@@ -131,6 +131,9 @@ const searchTimer = ref(null);
 const searchStock = async (keyword, stockIndex) => {
   // 防抖
   if (searchTimer.value) clearTimeout(searchTimer.value);
+  // 赋值当前激活的搜索下标
+  activeSearchIndex.value = stockIndex;
+  
   if (!keyword || keyword.length < 2) {
     searchResults.value = [];
     activeSearchIndex.value = -1;
@@ -149,6 +152,7 @@ const searchStock = async (keyword, stockIndex) => {
     } catch (err) {
       console.error('搜索股票失败:', err);
       searchResults.value = [];
+      activeSearchIndex.value = -1;
     }
   }, 300);
 };