fix(chu): 添加 Umiguri 新版本头部标签到静默忽略列表

添加 @MAINBPM @usetil @ENDHEAD @BGSCENE @FLDSCENE @RLDATE @cmt
这些标签是 Umiguri 新版本使用的元数据/渲染相关标签，对转谱不影响

Author: Applesaber

parser/chu/UgcParser.cs

@@ -184,6 +184,8 @@ private void ParseHeaderLine(string line, ChuChart chart, List<Alert> alerts, in
             case "@JACKET": case "@BGIMG": case "@BGMODE": case "@FLDCOL": case "@FLDIMG":
             case "@FLAG": case "@ATINFO": case "@DLURL": case "@COPYRIGHT": case "@LICENSE":
             case "@MAINTIL": case "@TIL":
+            case "@MAINBPM": case "@USETIL": case "@ENDHEAD":
+            case "@BGSCENE": case "@FLDSCENE": case "@RLDATE": case "@CMT":
                 break;
 
             case "@SPDMOD":