Test Keycloak JWT validation against access token issued via NextAuth; ensure Spring Boot resource server correctly validates token signature, expiration, issuer, and optional audience.
Add a docker-compose.yml to run a local development stack: Postgres (with mounted init scripts), Redis, MinIO, Keycloak (start-dev) and pgAdmin, plus a bridge network and persistent volumes. Also add init/init.sql to create the keycloak database and grant privileges to the admin user so Keycloak can connect to its dedicated DB. Default credentials and port mappings are provided for development convenience.
