feat: add combat and deleveling AI

Client/Domain/AI/Combat/CombatZone.cs

@@ -0,0 +1,25 @@
+using Client.Domain.Common;
+using Client.Domain.ValueObjects;
+
+namespace Client.Domain.AI.Combat
+{
+    public class CombatZone : ObservableObject
+    {
+        public CombatZone(Vector3 center, float radius)
+        {
+            Center = center;
+            Radius = radius;
+        }
+
+        public bool IsInside(Vector3 point)
+        {
+            return Center.HorizontalDistance(point) <= Radius;
+        }
+
+        public Vector3 Center { get { return center; } set { if (center != value) { center = value; OnPropertyChanged(); } }}
+        public float Radius { get { return radius; } set { if (radius != value) { radius = value; OnPropertyChanged(); } }}
+
+        private float radius;
+        private Vector3 center = new Vector3(0, 0, 0);
+    }
+}