Add healing effects and systems with event handling

GameCore/Combat/Effects/HealEffect.cs

@@ -0,0 +1,14 @@
+using GameCore.Combat.Interfaces;
+using GameCore.Events;
+
+namespace GameCore.Combat.Effects;
+
+public class HealEffect(float amount) : IEffect
+{
+    public void Execute(EffectContext context)
+    {
+        if (context.Target == null) return;
+
+        context.World.PublishEvent(new HealDealtEvent(context.Target.Value, amount));
+    }
+}

GameCore/Combat/HealingSystem.cs

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+using GameCore.Attributes;
+using GameCore.ECS;
+using GameCore.ECS.Interfaces;
+using GameCore.Events;
+using Attribute = GameCore.Attributes.Attribute;
+
+namespace GameCore.Combat;
+
+public class HealingSystem : ISystem
+{
+    private readonly World _world;
+
+    public HealingSystem(World world)
+    {
+        _world = world;
+        _world.Subscribe<HealDealtEvent>(OnHealDealt);
+    }
+
+    public void Update(World world, float deltaTime)
+    {
+    }
+
+    private void OnHealDealt(HealDealtEvent e)
+    {
+        var attributes = _world.GetComponent<AttributeComponent>(e.Target);
+        if (attributes == null) return;
+
+        var currentHealth = attributes.GetValue(Attribute.Health);
+        var maxHealth = attributes.GetValue(Attribute.MaxHealth);
+
+        if (currentHealth >= maxHealth) return;
+
+        var amountToHeal = e.Amount;
+        var newHealth = currentHealth + amountToHeal;
+
+        if (newHealth > maxHealth)
+        {
+            amountToHeal = maxHealth - newHealth;
+            newHealth = maxHealth;
+        }
+
+        attributes.ModifyValue(Attribute.Health, amountToHeal);
+
+        _world.PublishEvent(new EntityHealedEvent(e.Target, newHealth, amountToHeal));
+    }
+}

GameCore/Events/EntityHealedEvent.cs

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+using GameCore.ECS;
+using GameCore.Events.Interfaces;
+
+namespace GameCore.Events;
+
+public readonly struct EntityHealedEvent(Entity target, float newHealth, float amountHealed) : IEvent
+{
+    public readonly Entity Target = target;
+    public readonly float NewHealth = newHealth;
+    public readonly float AmountHealed = amountHealed;
+}

GameCore/Events/HealDealtEvent.cs

@@ -0,0 +1,10 @@
+using GameCore.ECS;
+using GameCore.Events.Interfaces;
+
+namespace GameCore.Events;
+
+public readonly struct HealDealtEvent(Entity target, float amount) : IEvent
+{
+    public readonly Entity Target = target;
+    public readonly float Amount = amount;
+}