Add event publishing for inventory and combat interactions

GameCore/Events/EntityDamagedEvent.cs

@@ -0,0 +1,11 @@
+using GameCore.ECS;
+using GameCore.Events.Interfaces;
+
+namespace GameCore.Events;
+
+public readonly struct EntityDamagedEvent(Entity target, float newHealth, float damageTaken) : IEvent
+{
+    public readonly Entity Target = target;
+    public readonly float NewHealth = newHealth;
+    public readonly float DamageTaken = damageTaken;
+}