Added Tile collision detection

PuzzleTile.cs

@@ -0,0 +1,28 @@
+using Godot;
+
+public partial class PuzzleTile : Sprite2D
+{
+    // Public properties so the GameBoard can read/write them
+    public int GridX { get; set; }
+    public int GridY { get; set; }
+    public bool IsMoving { get; private set; } = false;
+
+    private int _tileSize = 128;
+
+    // The board will call this method when it calculates a valid move
+    public void SlideTo(int targetX, int targetY)
+    {
+        // Calculate distance for animation speed
+        float distance = Mathf.Abs(targetX != GridX ? targetX - GridX : targetY - GridY) * _tileSize;
+        float tweenDuration = distance / 600.0f;
+
+        GridX = targetX;
+        GridY = targetY;
+        Vector2 targetPixelPos = new Vector2(GridX * _tileSize, GridY * _tileSize);
+
+        IsMoving = true;
+        Tween tween = CreateTween();
+        tween.TweenProperty(this, "position", targetPixelPos, tweenDuration);
+        tween.Finished += () => IsMoving = false;
+    }
+}