feat(战斗系统): 添加内伤机制和爆炸类型子弹

为子弹系统添加新的爆炸类型(MotionType.EXPLOSION)
实现内伤机制，包括内伤子弹和相关逻辑
修改多个子弹场景以使用爆炸类型
调整格挡系统，增加内伤效果
更新武器描述和角色配置

components/Bullets/InternalDamage.tscn

@@ -0,0 +1,30 @@
+[gd_scene format=3 uid="uid://dnjct3fifocnb"]
+
+[ext_resource type="PackedScene" uid="uid://crtdkysmnkith" path="res://components/Abstracts/BulletBase.tscn" id="1_xwju0"]
+[ext_resource type="Texture2D" uid="uid://mo0gjwh5amev" path="res://resources/effects/danger/Effect_Boss_YiGung_Upper1206.png" id="2_0na4i"]
+[ext_resource type="Script" uid="uid://d3m2bjkxg82a2" path="res://scripts/Contents/Bullets/InternalDamage.gd" id="2_nsbh7"]
+
+[sub_resource type="SpriteFrames" id="SpriteFrames_nsbh7"]
+animations = [{
+"frames": [{
+"duration": 1.0,
+"texture": ExtResource("2_0na4i")
+}],
+"loop": true,
+"name": &"default",
+"speed": 5.0
+}]
+
+[sub_resource type="CircleShape2D" id="CircleShape2D_0na4i"]
+radius = 150.0
+
+[node name="InternalDamage" unique_id=5571707 instance=ExtResource("1_xwju0")]
+script = ExtResource("2_nsbh7")
+
+[node name="texture" parent="." index="0" unique_id=162977358]
+scale = Vector2(0.25103292, 0.25103292)
+sprite_frames = SubResource("SpriteFrames_nsbh7")
+
+[node name="hitbox" parent="." index="1" unique_id=175349408]
+shape = SubResource("CircleShape2D_0na4i")
+disabled = true