Gap: 1112 hypotheses have no rows in hypothesis_papers (no evidence links). Query 20: SELECT h.id, h.title FROM hypotheses h WHERE NOT EXISTS (SELECT 1 FROM hypothesis_papers hp WHERE hp.hypothesis_id=h.id) LIMIT 20. For each, search PubMed/Semantic Scholar for 2-4 supporting papers, create hypothesis_papers rows. Prefer papers already in the papers table by pmid/doi match. Acceptance: 15+ hypotheses get 2+ paper links.