SQLite (cp the ext DB file) and Postgres (rename/copy schema) recipes.
Key trap documented: dbversions is keyed by ext id and m001 drops the
legacy v1 tables, so the new install must seed dbversions['spirekeeper']
>= 1 to skip m001 and preserve copied data. Validated on the regtest
dev instance (10 tables, 52 dca_payments etc. preserved across boot).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
