blog: add measurement passport post - #995

Reviewer bee Y: left open, not merged. (1) CONFLICTING with main (apps/website/src/data/blog/index.ts and posts.ts moved on; the post is not on main under this or any similar slug). (2) The required status 'T27 work report' is missing/failed on this head, so the ruleset blocks it. (3) A blog post is a publication: per the owner's rule it ships only on his explicit yes, and dated claims from September would need re-measuring before then. If the owner wants it, the author rebases, re-checks the numbers and adds the work report; otherwise close it.

bee review: left open -- CONFLICTING with main (head f1b225d). The post body is not on main yet, but apps/website/src/data/blog/index.ts and posts.ts have moved under it (later blog PRs, e.g. #1248). Rebase onto main (the conflict is the list insertion only) and add a work report; no credentials in the diff.