build: add PDF generation step (xml2rfc --pdf with weasyprint fallback)

build.sh

@@ -43,8 +43,27 @@ echo "Generating text output..."
 echo "Generating HTML output..."
 "$XML2RFC" "$DIR/$DRAFT.xml" --html --quiet 2>/dev/null
 
+# Step 4: XML -> PDF (requires weasyprint + pangocffi + pycairo injected into xml2rfc venv
+# and pydyf<0.10 pinned; see /home/c/projects/research.ietf/workspace/drafts/README-pdf.md)
+echo "Generating PDF output..."
+if "$XML2RFC" "$DIR/$DRAFT.xml" --pdf --quiet 2>/dev/null; then
+  PDF_OK=1
+else
+  echo "  xml2rfc --pdf failed; falling back to weasyprint on HTML"
+  if command -v weasyprint >/dev/null 2>&1; then
+    weasyprint "$DIR/$DRAFT.html" "$DIR/$DRAFT.pdf" >/dev/null 2>&1 && PDF_OK=1 || PDF_OK=0
+  else
+    PDF_OK=0
+  fi
+fi
+
 echo ""
 echo "Build complete:"
 echo "  $DRAFT.xml   (submit this to datatracker)"
 echo "  $DRAFT.txt"
 echo "  $DRAFT.html"
+if [ "${PDF_OK:-0}" = "1" ]; then
+  echo "  $DRAFT.pdf"
+else
+  echo "  (PDF generation skipped — missing deps)"
+fi