Abbreviate note labels in Piano Roll

Nobody has claimed this yet.

### Enhancement Summary

I know there's more work already being done with the labels but here's a quick thought. If a note is too short to allow the full label (e.g. "G# / Ab 4"), let it display some shorter portion that does fit (e.g. "G# / Ab", or just "G#").
Right now, on medium-length notes (where shorter labels fit, but longer ones don't), it feels like the empty space is going to waste.

(maybe i should just stop writing in weird key signatures)

### Implementation Details / Mockup

The abbreviations (or the truncation points) should be pre-defined, otherwise you'd get incorrect labels like "G# / A"


### Please search the issue tracker for existing feature requests before submitting your own.

- [x] I have searched all existing issues and confirmed that this is not a duplicate.

Start by locating the Piano Roll note-label rendering entry point and inspect how labels are chosen for different note lengths. Define the permitted abbreviation points described in the issue, then verify that medium-length notes show the longest valid label without producing partial note names.

Written by the indexing model from the issue text.