fix: set position before adding grenade to tree, remove duplicate add_child

movement/player_movement_controller.gd

@@ -1131,7 +1131,8 @@ func _spawn_grenade_local(pos: Vector3, vel: Vector3, owner_id: int) -> void:
 	var g_scene = load("res://weapons/grenade_projectile.gd")
 	if not g_scene: return
 	var g = g_scene.new()
-	g.global_position = pos
+	# Set position before adding to tree to avoid global_transform warning
+	g.position = pos
 	g.velocity = vel
 	
 	var p = null