refactor(追踪系统): 统一使用getTrackingAnchor方法获取追踪目标位置

修改多个子弹脚本和EntityBase，使用统一的getTrackingAnchor方法获取追踪目标位置
在BulletBase中增加目标有效性检查
调整Wave配置和Rooster武器顺序

scripts/Statemachine/BulletBase.gd

@@ -59,15 +59,16 @@ func _physics_process(_delta: float) -> void:
 	if destroying: return
 	if is_instance_valid(launcher) and (launcher.isPlayer() or is_instance_valid(launcher.currentFocusedBoss)):
 		launcher.position -= Vector2.from_angle(rotation) * recoil
-		PresetAIs.trace(
-			self,
-			EntityTool.findClosetEntity(position, get_tree(),
-			!launcher.isPlayer(),
-			launcher.isPlayer(),
-			[launcher]
-			).position,
-			launcher.fields.get(FieldStore.Entity.BULLET_TRACE) / 10
-		)
+		var targetEntity = EntityTool.findClosetEntity(position, get_tree(),
+		!launcher.isPlayer(),
+		launcher.isPlayer(),
+		[launcher]		)
+		if is_instance_valid(targetEntity):
+			PresetAIs.trace(
+				self,
+				targetEntity.getTrackingAnchor(),
+				launcher.fields.get(FieldStore.Entity.BULLET_TRACE) / 10
+			)
 		ai()
 	else:
 		tryDestroy()
@@ -113,7 +114,8 @@ func tryRefract():
 		var value = launcher.fields.get(FieldStore.Entity.BULLET_REFRACTION)
 		var entity = EntityTool.findClosetEntity(position, get_tree(), !launcher.isPlayer(), launcher.isPlayer())
 		for i in range(MathTool.shrimpRate(value)):
-			refract(entity, i, value, value - floor(value))
+			if is_instance_valid(entity):
+				refract(entity, i, value, value - floor(value))
 
 # 抽象方法
 func ai():