"There are no guardrails that guarantee sounding good." nf-8ide ← Beads

Twinned from https://github.com/cfsh/ninefold/issues/260 by tools/beads/import_github.py's reconcile pass.

from https://github.com/cfsh/ninefold/discussions/258

"The roll is chromatic. A kid mashing X on random rows will produce dissonance, learn "I'm bad at this," and leave. Power for a novice comes from constraints that make failure impossible: a scale lock (default pentatonic, pick a key per song) means every note placed is a right note — Chrome Music Lab and every Novation groovebox live on this. It also composes beautifully with what exists: the roll just filters _pitches, the test keyboard shows fewer-but-always-right keys, and the kit rows are unaffected. This is probably the single highest engagement-per-line-of-code change available."

I am open to scale lock + single scale picker per song.

I have similar UX question to https://github.com/cfsh/ninefold/issues/259, where we put the scale picker, and an option to 'switch to unbounded scale'.

Please sketch/mock, don't implement yet.