fix: reformat code / code improvements

lib/viewmodels/bar_screen_view_model.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/foundation.dart';
 
+import '../models/payment_method.dart';
 import '../models/bar_tab.dart';
 import '../models/product.dart';
 import '../models/tab_item.dart';
@@ -33,7 +34,8 @@ class BarScreenViewModel extends ChangeNotifier {
 
     try {
       return _tabs.firstWhere((tab) => tab.id == _selectedTabId);
-    } catch (_) {
+    } catch (e) {
+      debugPrint('BarScreenViewModel: error finding selected tab: $e');
       return null;
     }
   }
@@ -58,7 +60,8 @@ class BarScreenViewModel extends ChangeNotifier {
           !_tabs.any((tab) => tab.id == _selectedTabId)) {
         _selectedTabId = _tabs.isEmpty ? null : _tabs.first.id;
       }
-    } catch (_) {
+    } catch (e) {
+      debugPrint('BarScreenViewModel: load error: $e');
       _errorMessage = 'Could not load bar screen.';
     } finally {
       _hasLoaded = true;
@@ -115,7 +118,7 @@ class BarScreenViewModel extends ChangeNotifier {
     await _reloadTabs();
   }
 
-  Future<void> closeSelectedTab({String paymentMethod = 'cash'}) async {
+  Future<void> closeSelectedTab({PaymentMethod paymentMethod = PaymentMethod.cash}) async {
     final tab = selectedTab;
 
     if (tab == null) return;
@@ -125,7 +128,7 @@ class BarScreenViewModel extends ChangeNotifier {
     await _reloadTabs();
   }
 
-  Future<void> closeTab(String tabId, {String paymentMethod = 'cash'}) async {
+  Future<void> closeTab(String tabId, {PaymentMethod paymentMethod = PaymentMethod.cash}) async {
     await barTabService.closeTab(tabId, paymentMethod: paymentMethod);
 
     await _reloadTabs();