Flips Phase 12 status to ✅ Code complete; bumps progress to 12/19 (63%). Closeout block summarizes the 8 implementation tasks, lists all new artifacts, calls out the 80-test count (was 60), and flags the Phase 14 deferred verifications (libargon2-dev compile + pamtester smoke). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>