feat(billing): show subscription quota usage in admin usage records (#6)

src/admin/pages/BillingPage.tsx

@@ -450,6 +450,11 @@ function UsageRecordsTable({
   result: PagedResult<UsageRecord>;
   onPage: (page: number) => void;
 }) {
+  const formatBillingSource = (row: UsageRecord) => {
+    if (row.billingSource === 'subscription') return '套餐额度';
+    return `¥${formatYuan(row.costCents)}`;
+  };
+
   return (
     <>
       <div className="admin-table-wrap">
@@ -474,8 +479,10 @@ function UsageRecordsTable({
                 </td>
                 <td className="billing-num">{row.inputTokens.toLocaleString()}</td>
                 <td className="billing-num">{row.outputTokens.toLocaleString()}</td>
-                <td className="billing-num">¥{formatYuan(row.costCents)}</td>
-                <td className="billing-num">¥{formatYuan(row.balanceAfterCents)}</td>
+                <td className="billing-num">{formatBillingSource(row)}</td>
+                <td className="billing-num">
+                  {row.billingSource === 'subscription' ? '—' : `¥${formatYuan(row.balanceAfterCents)}`}
+                </td>
               </tr>
             ))}
           </tbody>

src/admin/pages/DashboardPage.tsx

@@ -238,7 +238,9 @@ export function DashboardPage() {
                         <td>
                           in {row.inputTokens} / out {row.outputTokens}
                         </td>
-                        <td>¥{formatYuan(row.costCents)}</td>
+                        <td>
+                          {row.billingSource === 'subscription' ? '套餐额度' : `¥${formatYuan(row.costCents)}`}
+                        </td>
                       </tr>
                     ))
                   )}