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/smithlab2027charges/MANIFEST.json

@@ -1 +1 @@
-{"doc":"scienting-doc/1","files":[{"path":"document.json","sha256":"ca802f491901cb6c0ea6206b5ab61e05c06524def0182cff0478893823b25acc","size":665},{"path":"nodes.jsonl","sha256":"fd3f856a5dc20e7e6d5114da38d2cfffa35487d856d5221bf00c19195438de2c","size":8290},{"path":"provenance.json","sha256":"b1af404b3a07d4b102f0a45237285315dc1ff60f243636c22aef3e1c20b46912","size":224},{"path":"references.jsonl","sha256":"41551252af7b5fef0ba2a22dcc1f4a9512911803f0eda9d5e7c5a9f223fa48c7","size":339},{"path":"witnesses.json","sha256":"badd17f82e6cc4aa8d116d2056d10b868fbf6978fa47947d89404c458b6a532c","size":766}],"format":"scienting-package/1","key":"smithlab2027charges"}
+{"doc":"scienting-doc/1","files":[{"path":"document.json","sha256":"ca802f491901cb6c0ea6206b5ab61e05c06524def0182cff0478893823b25acc","size":665},{"path":"nodes.jsonl","sha256":"fd3f856a5dc20e7e6d5114da38d2cfffa35487d856d5221bf00c19195438de2c","size":8290},{"path":"provenance.json","sha256":"4bc7649bf6d3113f6c72b4016713654f57c8f03069632eabd1e6025c05cb9dac","size":226},{"path":"references.jsonl","sha256":"41551252af7b5fef0ba2a22dcc1f4a9512911803f0eda9d5e7c5a9f223fa48c7","size":339},{"path":"witnesses.json","sha256":"badd17f82e6cc4aa8d116d2056d10b868fbf6978fa47947d89404c458b6a532c","size":766}],"format":"scienting-package/1","key":"smithlab2027charges"}

fixtures/packages/smithlab2027charges/provenance.json

@@ -1 +1 @@
-{"note":"Built by hand for the conformance suite; every reading is synthetic.","stages":[{"processor":"local","stage":"hand","tool":"manuspec tools/build.py"}],"tools":[{"name":"manuspec tools/build.py","version":"0.1.0"}]}
+{"note":"Built by hand for the conformance suite; every reading is synthetic.","stages":[{"processor":"local","stage":"hand","tool":"paperspec tools/build.py"}],"tools":[{"name":"paperspec tools/build.py","version":"0.1.0"}]}