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>

.gitea/workflows/site.yml

@@ -0,0 +1,33 @@
+# Builds the website on every push to main and publishes it when the SITE_* secrets are set; see deploy/README.md.
+name: site
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+jobs:
+  site:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: prefix-dev/setup-pixi@v0.9.4
+        with:
+          pixi-version: v0.69.0
+      - name: Build the site
+        run: pixi run python tools/site.py --out _site
+      - name: Publish the site
+        env:
+          SITE_HOST: ${{ secrets.SITE_HOST }}
+          SITE_USER: ${{ secrets.SITE_USER }}
+          SITE_PATH: ${{ secrets.SITE_PATH }}
+          SITE_SSH_KEY: ${{ secrets.SITE_SSH_KEY }}
+        run: |
+          if [ -z "$SITE_HOST" ]; then
+            echo "SITE_HOST is not set, so the site was built but not published."
+            exit 0
+          fi
+          command -v rsync >/dev/null || (sudo apt-get update && sudo apt-get install -y rsync)
+          mkdir -p ~/.ssh
+          printf '%s\n' "$SITE_SSH_KEY" > ~/.ssh/site_key
+          chmod 600 ~/.ssh/site_key
+          ssh-keyscan -H "$SITE_HOST" >> ~/.ssh/known_hosts
+          rsync -az --delete -e "ssh -i ~/.ssh/site_key" _site/ "$SITE_USER@$SITE_HOST:$SITE_PATH/"