feat: integrate payment summary and adapter for staff earnings management

apps/mobile/packages/domain/lib/src/adapters/financial/payment_adapter.dart

@@ -0,0 +1,19 @@
+import '../../entities/financial/staff_payment.dart';
+
+/// Adapter for Payment related data.
+class PaymentAdapter {
+  
+  /// Converts string status to [PaymentStatus].
+  static PaymentStatus toPaymentStatus(String status) {
+    switch (status) {
+      case 'PAID':
+        return PaymentStatus.paid;
+      case 'PENDING':
+        return PaymentStatus.pending;
+      case 'FAILED':
+        return PaymentStatus.failed;
+      default:
+        return PaymentStatus.unknown;
+    }
+  }
+}