feat: 调整角色和子弹属性，优化游戏平衡

- 将DamageLabel的伤害值计算从round改为ceil，确保最小伤害为1
- 调整KukeChild的攻击冷却时间从100降低到50，并添加伤害倍率0.1
- 提高PurpleCrystalSmall子弹速度从12到15，缩小尺寸从0.8到0.6
- 缩短KukeMC技能冷却时间并增加召唤数量
- 更新测试波次配置，移除Chick和Bear

components/Bullets/PurpleCrystalSmall.tscn

@@ -22,12 +22,12 @@ radius = 2.23607
 modulate = Color(1.5, 1.5, 1.5, 1)
 script = ExtResource("2_it0pa")
 displayName = "微型紫水晶"
-speed = 12.0
+speed = 15.0
 damage = 1.0
 lifeDistance = 1400.0
 
 [node name="texture" parent="." index="0"]
-scale = Vector2(0.8, 0.8)
+scale = Vector2(0.6, 0.6)
 sprite_frames = SubResource("SpriteFrames_r86b3")
 
 [node name="hitbox" parent="." index="1"]