Two ADR-041 files landed on main in parallel (sdd-adoption and
renovate-runner-setup). Renames the SDD one to 042 and repoints its references
(SPEC_DRIVEN_DEVELOPMENT, constitution, .specify/adrs/README, sdd-gate.yml).
The renovate ADR keeps 041; its references are left untouched. Riding this PR
per request.
Refs #778
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>