Wave enemies (#9)

* Add enemy wave management and path following components

* cleanup

scripts/components/EnemyWaveManager.cs

@@ -0,0 +1,86 @@
+using Godot;
+using Godot.Collections;
+
+namespace Mr.BrickAdventures.scripts.components;
+
+[GlobalClass]
+public partial class EnemyWaveManager : Node
+{
+    [Export] public Path2D EnemyPath { get; set; }
+    [Export] public Array<PackedScene> EnemyScenes { get; set; } = [];
+    [Export] public float SpawnInterval { get; set; } = 1.0f; // Time between each enemy spawn
+    
+    private int _enemiesToSpawn;
+    private int _activeEnemies;
+    private Timer _spawnTimer;
+    
+    [Signal]
+    public delegate void WaveCompletedEventHandler();
+    
+    public override void _Ready()
+    {
+        _spawnTimer = new Timer();
+        _spawnTimer.WaitTime = SpawnInterval;
+        _spawnTimer.OneShot = false;
+        _spawnTimer.Timeout += SpawnNextEnemy;
+        AddChild(_spawnTimer);
+    }
+    
+    public void StartWave()
+    {
+        if (EnemyScenes.Count == 0 || EnemyPath == null)
+        {
+            GD.PrintErr("EnemyWaveManager: Enemy scenes or path not set!");
+            return;
+        }
+
+        _enemiesToSpawn = EnemyScenes.Count;
+        _activeEnemies = 0;
+        _spawnTimer.Start();
+    }
+    
+    private void SpawnNextEnemy()
+    {
+        if (_enemiesToSpawn <= 0)
+        {
+            _spawnTimer.Stop();
+            return;
+        }
+
+        var enemyIndex = EnemyScenes.Count - _enemiesToSpawn;
+        var enemyScene = EnemyScenes[enemyIndex];
+        
+        var pathFollowNode = new PathFollow2D();
+        EnemyPath.AddChild(pathFollowNode);
+        
+        var enemyInstance = enemyScene.Instantiate<Node2D>();
+        pathFollowNode.AddChild(enemyInstance);
+        
+        var pathFollowerComponent = enemyInstance.GetNodeOrNull<PathFollowerComponent>("PathFollowerComponent");
+        if (pathFollowerComponent == null)
+        {
+            GD.PrintErr($"Enemy scene '{enemyScene.ResourcePath}' is missing a PathFollowerComponent.");
+            pathFollowNode.QueueFree();
+            _enemiesToSpawn--;
+            return;
+        }
+        
+        pathFollowNode.Rotates = pathFollowerComponent.ShouldRotate;
+        pathFollowerComponent.Initialize(pathFollowNode);
+        pathFollowerComponent.StartFollowing();
+        pathFollowerComponent.EnemyDestroyed += OnEnemyDestroyed;
+
+        _enemiesToSpawn--;
+        _activeEnemies++;
+    }
+
+    private void OnEnemyDestroyed()
+    {
+        _activeEnemies--;
+        
+        if (_enemiesToSpawn == 0 && _activeEnemies == 0)
+        {
+            EmitSignalWaveCompleted();
+        }
+    }
+}