Top Up Balance logic and Added fixes for routing

frontend/pweb/lib/pages/wallet_top_up/header.dart

@@ -0,0 +1,47 @@
+import 'package:flutter/material.dart';
+
+import 'package:pweb/generated/i18n/app_localizations.dart';
+
+
+class WalletTopUpHeader extends StatelessWidget {
+  final VoidCallback onBack;
+  final String walletName;
+
+  const WalletTopUpHeader({
+    super.key,
+    required this.onBack,
+    required this.walletName,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final loc = AppLocalizations.of(context)!;
+
+    return Row(
+      children: [
+        IconButton(
+          icon: const Icon(Icons.arrow_back),
+          onPressed: onBack,
+        ),
+        const SizedBox(width: 8),
+        Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            Text(
+              loc.walletTopUpTitle,
+              style: theme.textTheme.titleLarge,
+            ),
+            const SizedBox(height: 4),
+            Text(
+              walletName,
+              style: theme.textTheme.bodyMedium?.copyWith(
+                color: theme.colorScheme.onSurfaceVariant,
+              ),
+            ),
+          ],
+        ),
+      ],
+    );
+  }
+}