refactor: extract shared payment status sets to utility module

- Move PAID_STATUSES/FAILED_STATUSES from Balance.tsx and TopUpResult.tsx
  to src/utils/paymentStatus.ts
- Eliminates code duplication between the two pages

src/pages/Balance.tsx

@@ -13,6 +13,7 @@ import type { PaginatedResponse, Transaction } from '../types';
 import { Card } from '@/components/data-display/Card';
 import { Button } from '@/components/primitives/Button';
 import { staggerContainer, staggerItem } from '@/components/motion/transitions';
+import { isPaidStatus, isFailedStatus } from '../utils/paymentStatus';
 
 // Icons
 const ChevronDownIcon = ({ className = 'h-5 w-5' }: { className?: string }) => (
@@ -64,32 +65,10 @@ export default function Balance() {
     if (paymentHandledRef.current) return;
 
     const paymentStatus = searchParams.get('payment') || searchParams.get('status');
-    const paidSet = new Set([
-      'succeeded',
-      'success',
-      'paid',
-      'paid_over',
-      'overpaid',
-      'completed',
-      'confirmed',
-      'closed',
-    ]);
-    const failedSet = new Set([
-      'fail',
-      'failed',
-      'error',
-      'canceled',
-      'cancelled',
-      'declined',
-      'expired',
-      'cancel',
-      'system_fail',
-      'refund_paid',
-    ]);
 
     const normalised = paymentStatus?.toLowerCase() ?? '';
-    const isSuccess = paidSet.has(normalised) || searchParams.get('success') === 'true';
-    const isFailed = failedSet.has(normalised);
+    const isSuccess = isPaidStatus(normalised) || searchParams.get('success') === 'true';
+    const isFailed = isFailedStatus(normalised);
 
     if (isSuccess) {
       paymentHandledRef.current = true;