feat: add equality operators, make history screen paginated, random performance updates

lib/models/closed_tab_item.dart

@@ -16,4 +16,25 @@ class ClosedTabItem {
   });
 
   int get lineTotalInCents => quantity * unitPriceInCents;
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is ClosedTabItem &&
+          id == other.id &&
+          closedTabId == other.closedTabId &&
+          productId == other.productId &&
+          productName == other.productName &&
+          quantity == other.quantity &&
+          unitPriceInCents == other.unitPriceInCents;
+
+  @override
+  int get hashCode => Object.hash(
+        id,
+        closedTabId,
+        productId,
+        productName,
+        quantity,
+        unitPriceInCents,
+      );
 }