feat(角色): 添加熊boss的新攻击方式和音效

添加熊boss的四种攻击方式：
1. 箭雨攻击(ArrowSeven)
2. 太阳舞攻击(SunDance)
3. 永恒彩虹攻击(ForeverRainbow)
4. 冲刺攻击(BearSprint)

新增对应攻击音效资源
调整子弹追踪和伤害计算逻辑
添加冲刺粒子特效

scripts/Contents/Bullets/BossAttack/Bear/ArrowSeven.gd

@@ -27,10 +27,10 @@ func ai():
 	if timeLived() <= forwardTime:
 		speed = 10 * ((forwardTime - timeLived()) / forwardTime)
 	elif forwarded:
-		if timeLived() < forwardTime + 1000:
+		if timeLived() < forwardTime + 2000:
 			speed = clamp((timeLived() - forwardTime) / 75, 0, 30)
 			if is_instance_valid(tracer):
-				PresetBulletAI.trace(self, tracer.position, 0.1)
+				PresetBulletAI.trace(self, tracer.position, 0.03)
 	else:
 		forwarded = true
 

scripts/Contents/Bullets/BossAttack/Bear/ForeverRainbow.gd

@@ -0,0 +1,20 @@
+extends BulletBase
+
+@export var allColor: GradientTexture1D = null
+
+var myColor: Color
+
+func register():
+	damage = 5
+	penerate = 1
+func spawn():
+	myColor = allColor.gradient.sample(randf())
+	setColor(myColor)
+
+func ai():
+	speed = (11000 - timeLived()) / 11000 * initialSpeed
+	rotation_degrees += speed / 10
+	PresetBulletAI.forward(self, rotation)
+
+func setColor(color: Color):
+	texture.modulate = color

scripts/Contents/Bullets/ChickSprint.gd

@@ -5,10 +5,10 @@ func register():
 	speed = 0
 	penerate = 1
 func ai():
-	damage = launcher.velocity.length()
+	damage = launcher.velocity.length() / 300
 	PresetBulletAI.lockLauncher(self, launcher, true)
 	if !launcher.sprinting:
 		tryDestroy()
 func destroy(beacuseMap: bool):
 	if beacuseMap:
-		launcher.takeDamage(self, 0.5)
+		launcher.takeDamage(self, MathTool.rate(0.5))