refactor(frontend): services/api 迁至 src/api，http 迁至 utils/request

对齐 Vue 后台惯例：
- src/api/          域 API（原 services/api）
- src/utils/request.ts  HTTP 封装（原 services/http.ts）
- src/utils/export.ts  客户端导出工具
- src/utils/index.ts   工具统一出口

全局导入改为 @/api 与 @/utils/request，tsc + build 通过。

frontend/src/components/deploy/CredentialFormDialog.tsx

@@ -8,7 +8,7 @@ import { Label } from '@/components/ui/label';
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
 import { Plus, Key, Globe, Container } from 'lucide-react';
 import { toast } from 'sonner';
-import { credentialApi, deployApi } from '@/services/api';
+import { credentialApi, deployApi } from '@/api';
 
 interface Repo {
   id: number; name: string; url: string; credential_id: number | null;