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/cloud/BillingRecordDialog.tsx

@@ -20,7 +20,7 @@ import {
 } from '@/components/ui/select';
 import { Loader2 } from 'lucide-react';
 import { toast } from 'sonner';
-import { billingApi } from '@/services/api';
+import { billingApi } from '@/api';
 import { providerLabels } from './CloudBillingHelpers';
 
 const emptyRecord = {

frontend/src/components/cloud/BillingRuleDialog.tsx

@@ -21,7 +21,7 @@ import {
 } from '@/components/ui/select';
 import { Loader2 } from 'lucide-react';
 import { toast } from 'sonner';
-import { billingApi } from '@/services/api';
+import { billingApi } from '@/api';
 import { providerLabels } from './CloudBillingHelpers';
 
 const emptyRule = { name: '', provider: '', metric: 'daily', threshold: '', operator: '>', enabled: true };

frontend/src/components/cloud/CloudAccountManager.tsx

@@ -24,7 +24,7 @@ import {
   RefreshCw,
   Loader2,
 } from 'lucide-react';
-import { cloudApi } from '@/services/api';
+import { cloudApi } from '@/api';
 import { CloudBrandIcon, getProviderColor } from '@/components/icons/CloudBrandIcon';
 
 const providerLabels: Record<string, string> = {

frontend/src/components/cloud/CloudBilling.tsx

@@ -26,7 +26,7 @@ import {
 } from 'lucide-react';
 import { toast } from 'sonner';
 import { useConfirm } from '@/components/ui/confirm-dialog';
-import { billingApi } from '@/services/api';
+import { billingApi } from '@/api';
 import { formatCurrency, StatCard, TrendChart, providerLabels, providerColors } from './CloudBillingHelpers';
 import { StatStrip } from '@/components/ui/stat-strip';
 import { BillingRecordDialog } from './BillingRecordDialog';

frontend/src/components/cloud/DomainManager.tsx

@@ -24,7 +24,7 @@ import {
   RefreshCw,
   Loader2,
 } from 'lucide-react';
-import { cloudApi } from '@/services/api';
+import { cloudApi } from '@/api';
 
 export function DomainManager() {
   const [domains, setDomains] = useState<any[]>([]);

frontend/src/components/cloud/PlatformManager.tsx

@@ -29,7 +29,7 @@ import {
   ExternalLink,
   Loader2,
 } from 'lucide-react';
-import { platformApi } from '@/services/api';
+import { platformApi } from '@/api';
 
 const typeLabels: Record<string, string> = {
   public: '公有云',

frontend/src/components/cloud/RegionManager.tsx

@@ -37,7 +37,7 @@ import {
   XCircle,
   Loader2,
 } from 'lucide-react';
-import { regionApi } from '@/services/api';
+import { regionApi } from '@/api';
 import { useConfirm } from '@/components/ui/confirm-dialog';
 import { toast } from 'sonner';