根据前端需求，优化功能。 Optimise functionality based on front-end requirements.

中文：
- 导出的本地音乐导出.txt文件新增“歌曲ID”字段。

English:
- Added "Song ID" field to the exported Local Music Export.txt file.

app/src/main/java/com/hwinzniej/getmusicid3info/MainActivity.java

@@ -326,7 +326,7 @@ private synchronized void writeToFile(Tag tag, String dfile) {
         File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), fileName);
         try {
             FileWriter fileWriter = new FileWriter(file, true);
-            fileWriter.write((tag.getFirst(FieldKey.TITLE) + "#*#" + tag.getFirst(FieldKey.ARTIST) + "#*#" + tag.getFirst(FieldKey.ALBUM) + "#*#" + dfile + "\n"));
+            fileWriter.write((tag.getFirst(FieldKey.TITLE) + "#*#" + tag.getFirst(FieldKey.ARTIST) + "#*#" + tag.getFirst(FieldKey.ALBUM) + "#*#" + dfile + "#*#" + progressPercent + "\n"));
             fileWriter.close();
         } catch (IOException e) {
             e.printStackTrace();