feat: 仪表盘成本统计数据驱动化 — CloudAccount新增MonthlyCost字段 + dashboard实时聚合云账号月费用

frontend/src/components/cloud/CloudAccountManager.tsx

@@ -196,9 +196,9 @@ export function CloudAccountManager() {
         <div className="grid grid-cols-2 gap-4">
           {filteredAccounts.map((account) => {
             const accessKey = account.access_key || account.accessKey || '';
-            const regionCount = account.region_count ?? account.regionCount ?? 0;
             const serverCount = account.server_count ?? account.serverCount ?? 0;
             const lastSync = account.last_sync || account.lastSync || account.created_at || '-';
+            const monthlyCost = account.monthly_cost ?? account.monthlyCost ?? 0;
             return (
               <Card key={account.id} className="bg-slate-800 border-slate-700">
                 <CardContent className="p-4">
@@ -257,8 +257,8 @@ export function CloudAccountManager() {
                   </div>
                   <div className="grid grid-cols-3 gap-4 mt-4 pt-4 border-t border-slate-700">
                     <div>
-                      <p className="text-xs text-slate-400">区域数</p>
-                      <p className="text-lg font-medium text-slate-100">{regionCount}</p>
+                      <p className="text-xs text-slate-400">月费用</p>
+                      <p className="text-lg font-medium text-emerald-400">¥{Number(monthlyCost).toLocaleString()}</p>
                     </div>
                     <div>
                       <p className="text-xs text-slate-400">服务器数</p>