fix: 缩小选择分组弹窗的搜索范围至分组自身信息，更新输入占位提示文案

frontend/src/views/Websites.vue

@@ -311,7 +311,7 @@
     <el-dialog v-model="groupSelectVisible" title="选择上游分组" width="min(85vw, 1200px)" destroy-on-close class="group-select-dialog custom-theme-dialog">
       <!-- 搜索框 -->
       <div class="dialog-search-bar" style="margin-bottom: 16px;">
-        <el-input v-model="groupSearchQuery" placeholder="输入上游名称、分组名称、分组 ID、倍率进行过滤..." clearable class="custom-theme-search">
+        <el-input v-model="groupSearchQuery" placeholder="输入分组名称、分组 ID、倍率进行过滤..." clearable class="custom-theme-search">
           <template #prefix>
             <el-icon><Search /></el-icon>
           </template>
@@ -1289,11 +1289,10 @@ const filteredGroupsForModal = computed(() => {
       return false
     }
     if (query) {
-      const matchUpstreamName = item.source.upstream_name.toLowerCase().includes(query)
       const matchGroupName = item.source.group_name.toLowerCase().includes(query)
       const matchGroupId = String(item.source.group_id).toLowerCase().includes(query)
       const matchRate = String(item.rate).toLowerCase().includes(query)
-      return matchUpstreamName || matchGroupName || matchGroupId || matchRate
+      return matchGroupName || matchGroupId || matchRate
     }
     return true
   })