[Feature]能否在.mp3文件中增加封面，专辑、歌词等信息

**思路和建议**
ffmpeg应该有此功能，先mark一下。

**参考代码**
提供代码参考

The issue mentions using ffmpeg to add cover art, album, and lyrics metadata to .mp3 files. Look at the existing music download and processing code in the repository to see how audio files are currently handled. Research ffmpeg command-line options for embedding metadata, then identify where in the codebase file post-processing occurs. A successful implementation will modify downloaded .mp3 files to include the specified metadata fields.

Escrita pelo modelo de indexação a partir do texto da issue.