fix theme / add history

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;
+}