Add new skills: Double Jump, Ground Pound, Brick Armor, and Brick Shield; implement skill removal signal in SkillManager (#11)

scripts/components/DoubleJumpSkillComponent.cs

@@ -0,0 +1,45 @@
+using System.Linq;
+using Godot;
+using Mr.BrickAdventures.scripts.interfaces;
+using Mr.BrickAdventures.scripts.Resources;
+
+namespace Mr.BrickAdventures.scripts.components;
+
+[GlobalClass]
+public partial class DoubleJumpSkillComponent : Node, ISkill
+{
+    [Export] private PackedScene _doubleJumpAbilityScene;
+    private PlayerController _playerController;
+    
+    public void Initialize(Node owner, SkillData data)
+    {
+        _playerController = owner as PlayerController;
+        if (_playerController == null)
+        {
+            GD.PrintErr("DoubleJumpSkillComponent must be a child of a PlayerController.");
+        }
+    }
+
+    public void Activate()
+    {
+        if (_playerController == null) return;
+
+        var hasAbility = _playerController.GetActiveAbilities().Any(ability => ability is DoubleJumpAbility);
+
+        if (!hasAbility)
+        {
+            var abilityInstance = _doubleJumpAbilityScene.Instantiate<DoubleJumpAbility>();
+            _playerController.AddAbility(abilityInstance);
+        }
+    }
+
+    public void Deactivate()
+    {
+        _playerController?.RemoveAbility<DoubleJumpAbility>();
+    }
+
+    public void ApplyUpgrade(SkillUpgrade upgrade)
+    {
+        
+    }
+}