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.
Adds Core-owned identity contracts, a Core-owned Better Auth database schema
(ekklesia_core_user/session/account/verification), a first-class Core-owned
migration source that coexists with module-owned migrations under the exact
existing migration system, and an explicit Better Auth construction boundary.
No authentication endpoint or sign-in UI is exposed yet (ADR 0010).
Co-Authored-By: Claude Sonnet 5 <[email protected]>
ekklesia