CLI Music Rename

`ed music rename`

Renames a track or a folder in place.

ed music rename <target> <name> [--folder] [--json]

Name	Type / values	Default	What it does
`target`	track path or query, or folder path with `--folder`	required	What to rename.
`name`	text	required	The new name, without the extension.
`--folder`	flag	off	Rename a folder rather than a track.
`--json`	flag	off	Emit JSON on stdout.

{
  "from": "alpha-song.mp3",
  "to": "Night Drive.mp3"
}

ed music rename alpha-song.mp3 "Night Drive"
ed music rename "beta tune" Interlude
ed music rename --folder Chill Calm

A track keeps its extension, so renaming alpha-song.mp3 to Night Drive gives Night Drive.mp3. A folder has no extension to keep and takes the name as given. The name is sanitised the same way mkdir sanitises it, a blank name exits 1, and renaming onto a name that already exists exits 1 rather than overwriting.

Without --folder the target goes through the same track resolution mv uses, so an ambiguous query exits 3 with the matches. With --folder the target has to be a real folder path and anything else exits 3. Favourites follow the new name, folders included, and the running player is told so playback does not break mid-track.