[Feature]下载下来的文件是“歌手名-文件名”，但是我想“文件名-歌手名”

下载下来的文件是“歌手名-文件名”，但是我想“文件名-歌手名”。

Look for the code that formats the filename after downloading a song. The project likely has a function that constructs the filename string using artist and title. Find where downloads are handled, examine the naming logic, and swap the order. Test by running the tool to download a song and verify the new filename format.

索引モデルが issue の本文から書いたものです。