feat: add view models for all entities

Client/Domain/Service/NpcHandler.cs

@@ -0,0 +1,30 @@
+using Client.Domain.Entities;
+using Client.Domain.Factories;
+using Client.Domain.ViewModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Client.Domain.Service
+{
+    public class NpcHandler : EntityHandler<NPC>
+    {
+        public override void OnCreate(NPC entity)
+        {
+            mainViewModel.AddNpc(entity);
+        }
+        public override void OnDelete(NPC entity)
+        {
+            mainViewModel.RemoveNpc(entity);
+        }
+
+        public NpcHandler(EntityFactoryInterface<NPC> factory, MainViewModelInterface mainViewModel) : base(factory)
+        {
+            this.mainViewModel = mainViewModel;
+        }
+
+        private readonly MainViewModelInterface mainViewModel;
+    }
+}