Introduce company_secrets and company_secret_versions tables for encrypted secret storage. Add EnvBinding discriminated union (plain vs secret_ref) to replace raw string env values in adapter configs. Add hiddenAt column to issues for soft-hiding. Improve migration system with journal-ordered application and manual fallback when Drizzle migrator can't reconcile history. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>