The plans/ directory predated the mikado method approach. Deleted all
completed and abandoned plans, converted the still-relevant
migrate-forgejo-from-brew into a lean mikado chain root card under
how-to/forgejo/, cleaned up dangling wiki-links across docs, and
fixed a stale "pre-commit" reference to "prek".
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>