feat: rename to paperspec and add the website

- Rename manuspec to paperspec everywhere outside pixi.toml: prose, the
  tools, provenance tool names and the fixture key derivations, so every
  fixture and vector is rebuilt.
- Move the namespace addresses under the site, mirroring the repository:
  schema $id https://paperspec.scient.ing/schemas/<file>, the JSON-LD
  context https://paperspec.scient.ing/context/scienting-1.jsonld, and
  term IRIs https://paperspec.scient.ing/vocab#<term>. Format
  identifiers (scienting-*) and URNs (urn:scienting:) are unchanged.
- tools/site.py (standard library only) builds _site/: every file of the
  repository at its own path, each Markdown file rendered as a page with
  sidebar navigation, heading anchors matching the forge's, folder
  listings, a vocabulary page for the context's IRIs, a heading search
  and a 404 page; light and dark themes.
- check.py builds the site and checks that every Markdown file has a
  page, every internal link and fragment resolves, no Markdown is left
  unrendered, and every $id, the context address and the vocabulary IRIs
  are files of the site.
- deploy/: a Caddyfile with the media types and CORS the data needs, and
  a guide; .gitea/workflows/site.yml builds on main and publishes with
  rsync when the SITE_* secrets are set.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

fixtures/records/qa-report.json

@@ -1 +1 @@
-{"at":"2026-10-12T10:00:00Z","by":"ana","delivery":"smithlab evidence pilot (fictional)","docs":["smithlab/hale2026harmonic"],"format":"scienting-qa-report/1","id":"a5bjeh6psabm9","receipts":["eqgbbpwb6725v","gena76nkb6cnc"],"reviewers":[{"bound":"0.316340","confidence":"0.95","errors":1,"key":"ana","method":"clopper-pearson","sampled":13}],"signature":{"key":"ana","scheme":"ed25519","value":"yPHZH2t0ugji1HQcuSOlVwEJA0hWw7Y9mEr4LISi7AcGlM0mEmSm6YtrDnQ8CgkWSQ3gdwEB6HwalV0talSHDg=="}}
+{"at":"2026-10-12T10:00:00Z","by":"ana","delivery":"smithlab evidence pilot (fictional)","docs":["smithlab/hale2026harmonic"],"format":"scienting-qa-report/1","id":"a5bjeh6psabm9","receipts":["eqgbbpwb6725v","gena76nkb6cnc"],"reviewers":[{"bound":"0.316340","confidence":"0.95","errors":1,"key":"ana","method":"clopper-pearson","sampled":13}],"signature":{"key":"ana","scheme":"ed25519","value":"bZkWcu2XLTeWXyZSygCDeB31qLfpdT8B3CuRzEy6GVxDplSOoQXRPlEU6nIwdPkiZhLjFCRw3Hn6nJIxkMAcCg=="}}