Pre-built container images for self-hosted installs

Gateway and web images are now published to a public container registry on every release, with :<version>, :<major>.<minor>, and :latest tags. Self-hosted customers can pull pre-built images instead of building from source. Each release also ships an installation tarball with a production compose file, defaults, and a bootstrap script — so a fresh install is download, bootstrap, and docker compose up -d without cloning the source.

No action required. Existing source-based installs continue to work unchanged.