add interactive keyboard viewer, fix parser, move spec PDF

interactive layout viewer with version tabs, modifier key highlighting,
dead key compositions, ISO enter spanning two rows, arrow cluster.
fix keylayout parser mapSet range handling, update PDF build scripts,
move eurkey-layout-complete.pdf to spec/.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/website.yml

@@ -35,6 +35,13 @@ jobs:
         run: |
           pip install fpdf2
           python3 scripts/generate_layout_pdf.py -o eurkey-macos.eu/pdf/
+      - name: Generate layout JSON
+        run: |
+          mkdir -p eurkey-macos.eu/data
+          for ver in v1.2 v1.3 v1.4 v2.0; do
+            python3 scripts/parse_keylayout.py "src/keylayouts/EurKEY ${ver}.keylayout" \
+              -o "eurkey-macos.eu/data/eurkey-${ver}.json"
+          done
       - uses: actions/configure-pages@v5
       - uses: actions/upload-pages-artifact@v3
         with: