Add type to objects.

lib/models/asset.dart

@@ -1,4 +1,5 @@
 // Local
+import '/models/item_type.dart';
 import '/models/tracked_item.dart';
 
 class Asset extends TrackedItem {
@@ -6,6 +7,7 @@ class Asset extends TrackedItem {
 
   Asset({
     super.id,
+    super.type = ItemType.asset,
     required super.name,
     required super.amount,
     required super.description,

lib/models/income.dart

@@ -1,12 +1,14 @@
 // Local
 import '/models/tracked_item.dart';
 import '/models/frequency.dart';
+import '/models/item_type.dart';
 
 class Income extends TrackedItem {
   static String amountText = "Revenue";
 
   Income({
     super.id,
+    super.type = ItemType.income,
     required super.name,
     required super.amount,
     required super.frequency,