feat(战斗): 添加剑砍特效并重构火山子弹碰撞检测

- 新增剑砍音效及特效资源
- 为火山子弹添加命中时触发剑砍特效
- 使用FollowPosition组件重构碰撞检测逻辑
- 简化动画轨道和碰撞体配置

scripts/Statemachine/FollowPosition.gd

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+@tool
+extends Node2D
+
+@export var target: Node2D
+@export var offsetPosition: Vector2 = Vector2.ZERO
+@export var offsetRotation: float = 0.0
+@export var enablePosition: bool = false
+@export var enableRotation: bool = false
+
+func _process(_delta):
+	if is_instance_valid(target):
+		if enablePosition:
+			global_position = target.global_position + offsetPosition
+		if enableRotation:
+			global_rotation = target.global_rotation + deg_to_rad(offsetRotation)

scripts/Statemachine/FollowPosition.gd.uid

@@ -0,0 +1 @@
+uid://ckc6guqib3rno