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/server/CloudServerImport.tsx

@@ -25,7 +25,7 @@ import {
   Search,
   AlertCircle,
 } from 'lucide-react';
-import { cloudApi } from '@/services/api';
+import { cloudApi } from '@/api';
 
 interface CloudServerImportProps {
   open: boolean;
@@ -73,7 +73,7 @@ export function CloudServerImport({ open, onClose }: CloudServerImportProps) {
   useEffect(() => {
     if (open) {
       loadAccounts();
-      import('@/services/api').then(({ credentialApi }) => {
+      import('@/api').then(({ credentialApi }) => {
         credentialApi.list().then(( res: any) => setCredentials(res?.list || []))
           .catch(() => setCredentials([]));
       });

frontend/src/components/server/ExcelServerImport.tsx

@@ -23,7 +23,7 @@ import {
   ChevronLeft,
   Loader2,
 } from 'lucide-react';
-import { regionApi, serverApi, credentialApi } from '@/services/api';
+import { regionApi, serverApi, credentialApi } from '@/api';
 
 interface RegionOption {
   id: string;

frontend/src/components/server/ServerFileBrowser.tsx

@@ -26,7 +26,7 @@ import {
   Minimize2,
 } from 'lucide-react';
 import { cn } from '@/lib/utils';
-import { serverApi } from '@/services/api';
+import { serverApi } from '@/api';
 
 interface FileItem {
   name: string;

frontend/src/components/server/ServerForm.tsx

@@ -25,7 +25,7 @@ import {
   SelectValue,
 } from '@/components/ui/select';
 import { Server, ChevronDown, Loader2, Save, Key, Shield } from 'lucide-react';
-import { credentialApi } from '@/services/api';
+import { credentialApi } from '@/api';
 
 // 表单数据结构
 export interface ServerFormData {

frontend/src/components/server/ServerManager.tsx

@@ -39,7 +39,7 @@ import {
   ChevronLeft,
   ChevronRight,
 } from 'lucide-react';
-import { serverApi } from '@/services/api';
+import { serverApi } from '@/api';
 import { ServerStatsStrip } from './ServerStatsStrip';
 import { useConfirm } from '@/components/ui/confirm-dialog';
 import { toast } from 'sonner';

frontend/src/components/server/TerminalDialog.tsx

@@ -13,7 +13,7 @@ import { Maximize2, Minimize2, X, Shield} from 'lucide-react';
 import { cn } from '@/lib/utils';
 import { attachTerminalResize, fitTerminal, mountXterm } from '@/lib/xterm-utils';
 import { useUserStore } from '@/store';
-import { credentialApi, serverCredentialApi } from '@/services/api';
+import { credentialApi, serverCredentialApi } from '@/api';
 import { toast } from 'sonner';
 
 interface TerminalDialogProps {

frontend/src/components/server/WebShell.tsx

@@ -29,7 +29,7 @@ import {
 import { Terminal as XTerm } from 'xterm';
 import { FitAddon } from 'xterm-addon-fit';
 import 'xterm/css/xterm.css';
-import { serverApi } from '@/services/api';
+import { serverApi } from '@/api';
 import { useUserStore } from '@/store';
 
 interface TerminalSession {