v0.3.1

Hardened immutable Thread dispatch proofs and copy-on-write scope baselines. Tightened Film Quality Gate to scan active control-plane film artifacts while separately validating adopted specialist outputs and domain QA. Clarified agent route names and their adco CLI mappings, and hardened section-aware brief extraction. Validation: make release-check PASS; GitHub Actions run 29183469781 PASS on Python 3.10 and 3.12; wheel install smoke PASS with adco 0.3.1. This release provides structural and traceability validation, not client approval or creative-quality acceptance for a real project.