refactor(ChainGun): 调整武器属性和子弹生成逻辑

修改ChainGun的数值属性和子弹生成方式，新增split参数控制子弹间距
调整BossBar的样式和位置，删除未使用的shader文件

shaders/FilledRing.gdshader

@@ -1,13 +0,0 @@
-shader_type canvas_item;
-uniform float inner:hint_range(0.0, 1.0, 0.01)=0.5;
-uniform float outer:hint_range(0.0, 1.0, 0.01)=0.75;
-uniform float alpha:hint_range(0.0, 1.0, 0.1)=0.5;
-void fragment() {
-	vec2 center=vec2(0.5);
-	float dist=distance(UV,center)*2.0;
-	if(dist<inner){
-		COLOR.a*=alpha;
-	}else{
-		COLOR.a*=float(inner<dist&&dist<outer);
-	}
-}

shaders/Light.gdshader

@@ -1,9 +0,0 @@
-shader_type canvas_item;
-uniform vec4 color:source_color;
-uniform float mixProgress:hint_range(0.0, 1.0, 0.01)=0.5;
-void fragment() {
-	float maxDistance=0.5;
-	float dist=distance(UV,vec2(0.5));
-	vec4 mixed=vec4(color.rgb,smoothstep(0,1,(maxDistance-dist)/maxDistance));
-	COLOR=mix(COLOR,mixed,mixProgress);
-}