docker-compose.yml pulls registry.reversed.dev. This variant builds from the
checkout instead and needs no .env — every variable falls back to a working
localhost default, so the stack comes up ready to register the first admin.
Also exposes Postgres on 5434 (clear of the dev database on 5433) and adds a
backend healthcheck so `depends_on` ordering is meaningful.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>