Add DamageNumberManager and DamageNumber for displaying damage feedback

scripts/UI/DamageNumber.cs

@@ -0,0 +1,41 @@
+using System.Globalization;
+using Godot;
+
+namespace Mr.BrickAdventures.scripts.UI;
+
+[GlobalClass]
+public partial class DamageNumber : Label
+{
+    [Export] public float Duration { get; set; } = 0.8f;
+    [Export] public float FallDistance { get; set; } = 40f;
+    [Export] public float HorizontalDrift { get; set; } = 15f;
+    
+    public void ShowDamage(float damageAmount, Vector2 position)
+    {
+        Text = Mathf.Round(damageAmount * 100f).ToString(CultureInfo.InvariantCulture);
+        GlobalPosition = position;
+        
+        var rng = new RandomNumberGenerator();
+        var horizontalOffset = rng.RandfRange(-HorizontalDrift, HorizontalDrift);
+
+        var startPosition = GlobalPosition;
+        var endPosition = GlobalPosition + new Vector2(horizontalOffset, FallDistance);
+
+        var startColor = Colors.White;
+        startColor.A = 1f;
+        Modulate = startColor;
+        
+        var tween = CreateTween();
+        tween.SetParallel();
+
+        tween.TweenProperty(this, "global_position", endPosition, Duration)
+            .SetTrans(Tween.TransitionType.Quad)
+            .SetEase(Tween.EaseType.In);
+            
+        tween.Chain().TweenProperty(this, "modulate:a", 0f, Duration * 0.5f)
+            .SetTrans(Tween.TransitionType.Sine)
+            .SetEase(Tween.EaseType.Out);
+
+        tween.TweenCallback(Callable.From(QueueFree));
+    }
+}