[h0ffmann]

Task

The site's Live section gets a button, "Check the DOIs now". The button calls refpulse, a
Unison HTTP service, and shows if each DOI of the book resolves at doi.org (owner's request:
"I want the DOI check to be implemented in the website ASAP").

• unison/refpulse/refpulse.u: the service. GET /health, and GET /check?doi=… (8 DOIs at
  most), JSON with Access-Control-Allow-Origin: *.
• unison/refpulse/README.md, "In plain words", and a short paragraph on the site: what Unison
  is, and that the deploy is the remote computation (the function itself is sent to Unison Cloud),
  while the click is an ordinary GET. Fanning out over machines (Remote.fork) is the next step.
• site/: the button, its states, and ?refpulse=<url> for a local test. The site still works
  when the service is down.
• just unison-install, just unison-serve, just unison-deploy. ucm comes from the new
  .#unison dev shell.
• .claude/settings.json: the mattpocock-skills plugin is on for every reader of the
  repository (owner's request), listed in .claude/skills/README.md.

Proof

The site, built with just site-build, in headless Chrome, with no ?refpulse= override. The
button is answered by refpulse deployed on Unison Cloud:

• just unison-install: exit 0. refpulse.u compiles against @unison/base 7.20.0,
  @unison/cloud 27.3.1 and @unison/routes 7.0.2.
• curl: /health gave 200. /check gave 302 for the book's DOI and 404 for a made-up DOI, with
  the CORS header.
• just check: pass. cd site && gleam test: 20 passed.

Deployed. just unison-deploy put refpulse on Unison Cloud. refpulse_url is its hash URL,
https://h0ffmann.unison-services.cloud/h/uidn3rn5oag2ww53c5h4tltjlje76o3nlm44ct7tyjarcn24j2eq;
/health gave 200, and /check 302 and 404, with CORS. Open: naming the service
(/s/refpulse) failed with 401 Unauthorized. A hash URL changes when the code changes, so put
/s/refpulse in refpulse_url once the name works.

Checklist

• A fact changed in prose/ is changed in prose-ste/ and prose-pt-BR/ too. (No prose changed.)
• Every new Markdown file has its cite line (PERSONAS.md).
• A change to a hard rule links its change proposal in docs/2-engineering/changes/. (No hard rule changed.)
• A journal entry is added if this change met a challenge worth recording.

🤖 Generated with Claude Code