fix theme / add history

lib/models/closed_tab.dart

@@ -0,0 +1,27 @@
+import 'package:intl/intl.dart';
+
+import 'closed_tab_item.dart';
+
+class ClosedTab {
+  final String id;
+  final String originalTabId;
+  final String customerName;
+  final DateTime closedAt;
+  final List<ClosedTabItem> items;
+
+  ClosedTab({
+    required this.id,
+    required this.originalTabId,
+    required this.customerName,
+    required this.closedAt,
+    required this.items,
+  });
+
+  int get itemCount => items.fold(0, (sum, item) => sum + item.quantity);
+
+  int get totalInCents =>
+      items.fold(0, (sum, item) => sum + item.quantity * item.unitPriceInCents);
+
+  String get formattedTotal =>
+      NumberFormat.simpleCurrency().format(totalInCents / 100);
+}

lib/models/closed_tab_item.dart

@@ -0,0 +1,19 @@
+class ClosedTabItem {
+  final String id;
+  final String closedTabId;
+  final String productId;
+  final String productName;
+  final int quantity;
+  final int unitPriceInCents;
+
+  ClosedTabItem({
+    required this.id,
+    required this.closedTabId,
+    required this.productId,
+    required this.productName,
+    required this.quantity,
+    required this.unitPriceInCents,
+  });
+
+  int get lineTotalInCents => quantity * unitPriceInCents;
+}