piano roll and midi colors

### Enhancement Summary

is it possible to change different pitch values in the piano roll to be different colors (and have that vary when the piano roll is showing the chromatic scale vs when the user selects a scale to show the colors based off of solfege (assuming you can select scales in LMMS))

https://github.com/LMMS/lmms/issues/7306

### Implementation Details / Mockup


### 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 reviewing issue #7306 and the linked mockup, then locate LMMS's piano-roll and scale-selection entry points. Clarify whether scale selection already exists and define the expected color mapping for chromatic pitches and solfege-based scales. Done means the piano roll visibly uses different pitch colors in both modes.

Written by the indexing model from the issue text.