Mistake: lastmod = build time, not edit time

Mistake: lastmod = build time, not edit time

A framework that stamps <lastmod> with the deploy timestamp tells Google every URL changed on every release. After 2-3 cries of wolf, the crawler ignores the field entirely.

Fix checklist:
— Source lastmod from the row's updated_at, not now() or build time
— Update that column only when body, title, or canonical content changes — not on a view-count or analytics write
— ✅ Two consecutive builds with no content edit produce identical lastmod values
— ✅ Use full W3C datetime with timezone: 2026-01-14T09:32:00+00:00, not just a date

Definition of done: pull 10 random URLs, diff today's sitemap against yesterday's. Any lastmod that moved must correspond to a real content change you can point to.