feat(战斗系统): 调整KukeMC的攻击逻辑和紫水晶子弹

为KukeMC角色减少召唤子体数量但增加紫水晶子弹数量，优化战斗节奏
添加紫水晶子弹的显示名称
移除PurpleCrystal类名定义
在EntityBase中新增died信号

components/Characters/KukeChild.tscn

@@ -26,12 +26,14 @@ animations = [{
 [node name="KukeChild" instance=ExtResource("1_3ohuq")]
 script = ExtResource("2_ywxbd")
 
+[node name="collect" parent="sounds" index="4"]
+stream = null
+
 [node name="texture" parent="." index="2"]
 sprite_frames = SubResource("SpriteFrames_5rcbd")
 animation = &"walk"
 
 [node name="normal" type="Node2D" parent="texture/weapons" index="0"]
-position = Vector2(47, 11)
 
 [node name="statebar" parent="." index="3"]
 position = Vector2(0, -125)