ci: build docs from SUMMARY.md rather than by walking the directory

.github/workflows/deploy-docs.yml

@@ -59,10 +59,15 @@ jobs:
           ls -la
           echo "DEBUG: Checking md-book binary:"
           ls -la /tmp/md-book/target/release/ || echo "md-book binary not found"
-          echo "DEBUG: Building with md-book fork..."
+          echo "Building with md-book (SUMMARY.md-driven)"
           rm -rf book/
-          /tmp/md-book/target/release/md-book -i . -o book || true
-          echo "DEBUG: Build completed with exit code: $?"
+          # `build .` reads book.toml, so it honours `src` and the SUMMARY.md
+          # ordering. The old `-i . -o book` pointed at the docs root, which has
+          # no SUMMARY.md, so md-book fell back to walking the directory and
+          # published 574 pages — archives, research notes and artefacts
+          # included — in path order rather than the 59 the summary declares.
+          /tmp/md-book/target/release/md-book build .
+          echo "Pages built: $(find book -name '*.html' | wc -l)"
 
       - name: Upload build artifact
         uses: actions/upload-artifact@v5