Content backend, phase 1, is live

What changed

Phase 1 of the site's content backend is live. News, build-log and research entries are now managed through a backend item system: entries live in a cloud item store, console-created entries must carry source references, and publishing requires a two-gate sign-off. Publishing synchronously regenerates the feed, the sitemap and the data-room index, and the public list and detail pages update with it — visible site-wide within a minute. Production data migrated in the same batch: 27 build-log entries and 57 sitemap entries reconciled item by item, with zero loss.

Release check

Verified end to end on production: create → two gates → publish → detail page's initial HTML carries the body → feed regeneration → rollback restore → unpublish returns 404, with the audit trail in chain. The production deployment reads READY via API.