The superpowers workflow methodology is no longer in use. Move the
methodology-neutral design spec to docs/specs/ as the project's design
ledger, drop the superpowers-bound implementation plan (it referenced
superpowers sub-skills), and remove the now-dead /docs/superpowers/
.gitignore entry.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
