Adds ADR 0013 documenting the durable Phase 4C decisions (permission
registry, evaluator baselines, grant/scope semantics, platform-owner
bootstrap, shared database pool, Origin enforcement, and what remains
deferred), cross-links it from the authorization/README docs, and
refreshes the pnpm doctor no-DATABASE_URL example output in README.md
and repository-workflow.md to include the authorization migration.
