Validate(root): optional startup/test check for tree authoring faults —
>1 slot child per node, empty word, duplicate sibling words, dead-end
node — traversing circular slots without looping (#3).
keypress subpackage: WaitForKey(ctx, cancel) cancels a context on any
keystroke for watch-style streaming commands, with per-GOOS cbreak
(linux TCGETS/TCSETS, BSD TIOCGETA/TIOCSETA) and a non-tty/unsupported
fallback that just waits on ctx. Lifts the last OpenBSD-specific bit out
of evpnc/maglevc's watch.go (#6).
docs: replace PROPOSAL.md with an RFC-2119 design.md (FR/NFR for the
library). Example now dogfoods Validate (a unit test) and keypress (a
bounded `watch` command).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>