Review-Gate finding: GROBID emits type="arXiv" (camel-case), not "arxiv".
XPath literal match silently returned empty strings for all real responses.
Fix: iterate idno elements and compare .lower() == "arxiv".
Test fixture updated to reflect real GROBID output (type="arXiv").
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>