refactor: fix bugs and improve architecture

- Fix double-execution bug in LevelStateHandler (coins/skills were committed twice per level)
- Fix DamageComponent to track multiple targets via HashSet instead of single node
- Fix HealthComponent: update health immediately, decouple from PlayerController via signal wiring in PlayerController
- Remove dead loop in SkillManager.RemoveSkill; simplify O(n²) throw skill loop
- Replace GetNode<T>(path) with .Instance across managers; add Instance to StatisticsManager/SpeedRunManager
- GameManager.GetPlayer() now uses EventBus.PlayerSpawned instead of scanning all scene nodes
- UIManager.UiStack: remove [Export], use private List<Control>
- PlayerState: extract DefaultLives constant, simplify CreateDefault()

scripts/components/HealthComponent.cs

@@ -1,6 +1,4 @@
-using System.Threading.Tasks;
 using Godot;
-using Mr.BrickAdventures;
 using Mr.BrickAdventures.Autoloads;
 
 namespace Mr.BrickAdventures.scripts.components;
@@ -20,27 +18,16 @@ public partial class HealthComponent : Node2D
 
     public override void _Ready()
     {
-        _floatingTextManager = GetNode<FloatingTextManager>(Constants.FloatingTextManagerPath);
+        _floatingTextManager = FloatingTextManager.Instance;
     }
 
-    public void SetHealth(float newValue)
-    {
-        _ = ApplyHealthChange(newValue);
-    }
-
-    public void IncreaseHealth(float delta)
-    {
-        _ = ApplyHealthChange(Health + delta);
-    }
-
-    public void DecreaseHealth(float delta)
-    {
-        _ = ApplyHealthChange(Health - delta);
-    }
+    public void SetHealth(float newValue) => ApplyHealthChange(newValue);
+    public void IncreaseHealth(float delta) => ApplyHealthChange(Health + delta);
+    public void DecreaseHealth(float delta) => ApplyHealthChange(Health - delta);
 
     public float GetDelta(float newValue) => newValue - Health;
 
-    private async Task ApplyHealthChange(float newHealth, bool playSfx = true)
+    private void ApplyHealthChange(float newHealth, bool playSfx = true)
     {
         newHealth = Mathf.Clamp(newHealth, 0.0f, MaxHealth);
         var delta = newHealth - Health;
@@ -53,39 +40,19 @@ public partial class HealthComponent : Node2D
         else
             _floatingTextManager?.ShowHeal(delta, GlobalPosition);
 
-        if (playSfx)
-        {
-            if (delta > 0f && HealSfx != null)
-            {
-                HealSfx.Play();
-            }
-            else if (delta < 0f && HurtSfx != null)
-            {
-                HurtSfx.Play();
-                await HurtSfx.ToSignal(HurtSfx, AudioStreamPlayer2D.SignalName.Finished);
-            }
-        }
-
         Health = newHealth;
 
+        if (playSfx)
+        {
+            if (delta > 0f)
+                HealSfx?.Play();
+            else
+                HurtSfx?.Play();
+        }
+
         if (Health <= 0f)
-        {
             EmitSignalDeath();
-            // Emit global event if this is the player
-            if (Owner is PlayerController)
-                EventBus.EmitPlayerDied(GlobalPosition);
-        }
         else
-        {
             EmitSignalHealthChanged(delta, Health);
-            // Emit global events if this is the player
-            if (Owner is PlayerController)
-            {
-                if (delta < 0f)
-                    EventBus.EmitPlayerDamaged(Mathf.Abs(delta), Health, GlobalPosition);
-                else
-                    EventBus.EmitPlayerHealed(delta, Health, GlobalPosition);
-            }
-        }
     }
 }