refactor(ChainGun): 调整武器属性和子弹生成逻辑

修改ChainGun的数值属性和子弹生成方式，新增split参数控制子弹间距
调整BossBar的样式和位置，删除未使用的shader文件

scripts/Contents/Bullets/ChainGun.gd

@@ -1,6 +1,7 @@
 extends BulletBase
 
 var count: int = 1
+var splits: float = 10.0
 
 @onready var anchor: Node2D = $"%anchor"
 
@@ -9,6 +10,6 @@ func spawn():
 		for i in BulletBase.generate(ComponentManager.getBullet("PurpleCrystalSmall"), launcher, anchor.global_position, rotation):
 			i.damage = damage
 			var dir = Vector2.from_angle(i.rotation).rotated(deg_to_rad(-90))
-			i.global_position += dir * (count - j * 2) * 20 / 2
+			i.global_position += dir * (count - j * 2) * splits / 2
 func ai():
 	PresetBulletAI.lockLauncher(self, launcher, true)