ledger top up functionality and few small fixes for project architechture and design

frontend/pweb/lib/models/payment/payment_state.dart

@@ -1,27 +0,0 @@
-enum PaymentState {
-  success,
-  failed,
-  cancelled,
-  processing,
-  unknown,
-}
-
-PaymentState paymentStateFromRaw(String? raw) {
-  final trimmed = (raw ?? '').trim().toUpperCase();
-  final normalized = trimmed.startsWith('PAYMENT_STATE_')
-      ? trimmed.substring('PAYMENT_STATE_'.length)
-      : trimmed;
-
-  switch (normalized) {
-    case 'SUCCESS':
-      return PaymentState.success;
-    case 'FAILED':
-      return PaymentState.failed;
-    case 'CANCELLED':
-      return PaymentState.cancelled;
-    case 'PROCESSING':
-      return PaymentState.processing;
-    default:
-      return PaymentState.unknown;
-  }
-}