refactor: enhance navigation robustness by introducing popSafe and safePushNamedAndRemoveUntil methods and updating their usage.

apps/mobile/packages/features/client/billing/lib/src/presentation/pages/pending_invoices_page.dart

@@ -3,6 +3,7 @@ import 'package:design_system/design_system.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:flutter_modular/flutter_modular.dart';
+import 'package:krow_core/core.dart';
 
 import '../blocs/billing_bloc.dart';
 import '../blocs/billing_state.dart';
@@ -20,6 +21,7 @@ class PendingInvoicesPage extends StatelessWidget {
           appBar: UiAppBar(
             title: t.client_billing.awaiting_approval,
             showBackButton: true,
+            onLeadingPressed: () => Modular.to.toClientBilling(),
           ),
           body: _buildBody(context, state),
         );