feat(子弹系统): 重构伤害计算并添加音效

将子弹的伤害属性从`damage`重命名为`baseDamage`，并引入`damageMultipliers`数组支持多段伤害
为火山武器添加三段攻击音效并调整伤害倍率
更新相关武器和子弹脚本以适配新的伤害系统

scripts/Contents/Weapons/NuclearBomb.gd

@@ -9,6 +9,6 @@ func attack(entity: EntityBase):
 	var weaponPos = entity.findWeaponAnchor("normal")
 	for j in BulletBase.generate(ComponentManager.getBullet("NuclearBomb"), entity, weaponPos, weaponPos.angle_to_point(get_global_mouse_position())):
 		var bullet: NuclearBomb = j
-		bullet.damage = readStore("atk")
+		bullet.baseDamage = readStore("atk")
 		bullet.radius = readStore("radius")
 	return true