Two different controls in the Extract row are both called "All" #659

Reported as part of #657.

What goes wrong

Two buttons sit in the Extract row, a few pixels apart, both labelled All, meaning different things:

• #stemAllBtn means every stem: vocals, drums, bass, guitar, piano, other.
• The button inside #vocalModeToggle means the vocals as one track, as opposed to Lead + Backing.

The vocal toggle is shown whenever Vocals is selected, which is the default, so both are on screen together in the state most people open the app in. The reporter of #657 read them as a duplicate control and asked why there are two.

Why it is confusing rather than merely redundant

The words are the same and the scope is not. One is about which instruments come out; the other is about how one of those instruments is divided. Pressing the wrong one does something quite different from what the label suggests, and nothing on screen distinguishes them.

Constraints for whoever fixes it

• It is a rename, not a redesign. The stem row's All is the older and more general meaning, so the vocal one is the one that should change.
• Whatever it becomes has to sit beside "Lead + Backing" and read as its opposite. "One track", "Together" and "Single" are all candidates; none is obviously right.
• Ten language tables, and the replacement has to stay short in all of them. The toggle is two buttons wide inside a row that already collapses on small windows, so a long word in German or Portuguese costs layout (see the footer work in [Bug]: StemDeck UI Scaling in Windows #586).
• vocalMode.all is the key. Renaming the value is enough; renaming the key would touch more than it needs to.