chore(spec): leave the two registry projections to the publish lane

The pull-request stage generates spec-changes.json and the upgrade guide in
memory and compares no committed copy; a registry-entry PR needs no
regeneration commit.

Claude-Session: https://claude.ai/code/session_01KNKBCRDJCu5tGy3TEbvtrF
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude