ADR 0021 records the catch-up rules and amends ADR 0003 and 0005, whose
claims about secondary profiles were false. architecture.md, CLAUDE.md
and the migration rule describe the two migration paths; the guide tells
where the pre-update copy lives and how to remove a database a deletion
on Linux left behind.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>