Upgrade UMLS data from 2021 to latest release

[AlexMikhalev]

Summary

Current words_cui.tsv is from April 2021. Download fresh 2025/2026 UMLS release using new UMLS account credentials. Rebuild umls_automata.bin.zst artifact.

Details

• Current automata has ~1.4M patterns from 2021 UMLS release
• New release will have updated concepts, retired CUIs, and new terms
• Validate pattern count and entity extraction quality against 18 evaluation cases
• Ensure no regression in safety gate behavior (e.g., Pembrolizumab/EGFR blocking)

Acceptance Criteria

• Download latest UMLS release (2025AA or 2026AA)
• Rebuild umls_automata.bin.zst with updated data
• All 18 evaluation cases still pass 3-gate harness
• Document pattern count delta (old vs new)

Priority: P2