- Add MultiPoolService: registry of named Sequelize pools with create/get/close/healthcheck
- Add multi-pool config: write host + read replica host with separate ports
- Add DB_CONNECTION_STRING and DB_READ_HOST/DB_READ_PORT env vars
- Add docker-compose.ha.yml: Patroni + etcd cluster, HAProxy, PgBouncer
- Add HAProxy config: routes 5432 (write/primary) / 5433 (read/replica)
- Add PgBouncer userlist template
- Update dev/prod/staging configs with multi-pool hosts
Co-authored-by: Cursor <cursoragent@cursor.com>

- Add oidc-provider v9 for OIDC/OAuth2 authentication
- Add MongoDB client service for audit logging (sso_audit database)
- Add audit logger service with retry queue (up to 3 retries, 60s timeout)
- Add audit repository (insert, findByUserId, findByEventType)
- Add OIDC PostgreSQL adapter (grants storage)
- Add Handlebars views (login, register, consent)
- Add OIDC config service (issuer, TTL, cookie keys)
- Add oidc-grants and clients SQL migrations
- Update docker-compose: add PostgreSQL, MongoDB, rename containers
- Update .env.example: add OIDC, MongoDB, PostgreSQL variables
- Update package.json: add oidc-provider, mongodb, express-handlebars
- Update README with OIDC endpoints and architecture diagram
Co-authored-by: Cursor <cursoragent@cursor.com>

Co-authored-by: Cursor <cursoragent@cursor.com>