feat: url-test支持手动选择、节点组fixed节点使用角标展示 (#840)

* feat: allow manual selection of url-test group

* feat: fixed proxy indicator

* fix: try to fix traffic websocket no longer updating

* fixup: group delay test use defined url

src/services/types.d.ts

@@ -64,6 +64,7 @@ interface IProxyItem {
   hidden?: boolean;
   icon?: string;
   provider?: string; // 记录是否来自provider
+  fixed?: string; // 记录固定(优先)的节点
 }
 
 type IProxyGroupItem = Omit<IProxyItem, "all"> & {