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/packages/hale2026harmonic.checks-only/document.json

@@ -1 +1 @@
-{"counts":{"leaves":45,"nodes":75},"fidelity":{"counts":{"F0":1,"F1":4,"F2":13,"F3":27},"lowest":"F0"},"format":"scienting-doc/1","hashing":{"key_id":"ba87f5b02064d529","scheme":"hmac-team"},"key":"hale2026harmonic","kind":"article","language":"en","license":{"text":"All rights reserved by the publisher (fictional)."},"meta":{"DOI":"10.5555/example.hale.2026","author":[{"family":"Hale","given":"R."},{"family":"Osei","given":"M."}],"container-title":"Journal of Example Chemistry","issued":{"date-parts":[[2026,3,2]]},"page":"101-109","title":"Harmonic bond parameters for small organic molecules from a two-step fit","type":"article-journal","volume":"14"},"meta_hash":"831ac4c47c87df2bc0d761e169f3aefb3b2e64404a2d2b157a692262a956301f","policy":"checks-only","relations":[],"rev":12,"root":"1fd39f356fbbdbe306b68ed01d71ce1acf9a46310658f430b0e6c5581f5fce6b","store":"smithlab","version":{"date":"2026-03-02","type":"version-of-record"},"work":{"key":"hale2026harmonic","same_as":["doi:10.5555/example.hale.2026"]}}
+{"counts":{"leaves":45,"nodes":75},"fidelity":{"counts":{"F0":1,"F1":4,"F2":13,"F3":27},"lowest":"F0"},"format":"scienting-doc/1","hashing":{"key_id":"dc3a5e64b55a972b","scheme":"hmac-team"},"key":"hale2026harmonic","kind":"article","language":"en","license":{"text":"All rights reserved by the publisher (fictional)."},"meta":{"DOI":"10.5555/example.hale.2026","author":[{"family":"Hale","given":"R."},{"family":"Osei","given":"M."}],"container-title":"Journal of Example Chemistry","issued":{"date-parts":[[2026,3,2]]},"page":"101-109","title":"Harmonic bond parameters for small organic molecules from a two-step fit","type":"article-journal","volume":"14"},"meta_hash":"c74d73e3503619324cdd716399970b84f612496547da16f2713a7f789215dd27","policy":"checks-only","relations":[],"rev":12,"root":"1a0ae11b02b2f49ebbbf856bb09fe80731514bbeaad50cbb973ba0389b8ed7b2","store":"smithlab","version":{"date":"2026-03-02","type":"version-of-record"},"work":{"key":"hale2026harmonic","same_as":["doi:10.5555/example.hale.2026"]}}