cull(engine-cleanup): pass-8 phase-2 cascade round 1

[trim] fully-unreachable files deleted: 6
[trim] files edited: 55, files deleted: 0, nodes removed: 244
[type-trim] files edited: 1, types removed: 1

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.BattleEngine/Engine/Effect.cs

@@ -23,11 +23,6 @@ public class Effect : MonoBehaviour
 		_buff = false;
 	}
 
-	public void ChangeParticleColor(Color color)
-	{
-		MotionUtils.ChangeParticleSystemColor(m_ParticleSystem.gameObject, color);
-	}
-
 	public GameObject GetGameObjIns()
 	{
 		return m_GameObjIns;