feat(Bear): 添加新的攻击类型SunDance

为Bear角色添加新的攻击类型SunDance，包含子弹特效和动画。修改了Bear.gd以支持新攻击类型，并创建了SunDance.gd脚本和对应的场景文件。新攻击会生成旋转的彩色子弹，具有不同的颜色和大小变化效果。

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

@@ -0,0 +1,28 @@
+extends BulletBase
+
+@export var allColor: GradientTexture1D = null
+
+@onready var leave1: Sprite2D = $"%leave1"
+@onready var leave2: Sprite2D = $"%leave2"
+@onready var leave3: Sprite2D = $"%leave3"
+@onready var leave4: Sprite2D = $"%leave4"
+
+var myColor: Color
+
+func register():
+	speed = 0
+	damage = 5
+	penerate = 1
+func spawn():
+	myColor = allColor.gradient.sample(randf())
+	setColor(myColor)
+
+func ai():
+	rotation_degrees += 1
+	PresetBulletAI.lockLauncher(self, launcher, true)
+
+func setColor(color: Color):
+	leave1.modulate = Color(color) * 2
+	leave2.modulate = Color(color) * 4
+	leave3.modulate = Color(color) * 8
+	leave4.modulate = Color.WHITE * 16