Proposal: add-docker-core-deploy-target

Railway has a proven one-click Core deploy and Fly.io has a proven one-command launch, but the Docker path still demands a repository clone, a large env file, and the development/owner compose stack — the owner's words: "right now I am overwhelmed looking at the link for docker." The standalone Core image already contains everything needed; what is missing is two small image gaps (no localhost origin default, no first-boot owner credential) and a deliberately small user-facing surface (one docker run quickstart, one minimal production compose) per design-notes/deploy-surface-parity-2026-06-10.md and docs/research/deploy-button-parity-prior-art-2026-06-10.md.

The design note sized this as "a shell script entrypoint." The selected shape is a small ESM module (deploy/railway/core-first-boot.mjs) called by the existing core-supervisor.mjs before it spawns the reference and console. Rationale: the supervisor is already the image CMD and already owns child env construction; a Node module is unit-testable offline with node --test (scripts/docker-core-first-boot.test.mjs), needs no openssl/shell quoting, and keeps one process tree (no exec-chain). The CMD is unchanged, so the published Railway template keeps working byte-for-byte.

The standalone Core image SHALL boot a complete node from a single docker run with only a published port and a named data volume (Dockerfile targets railway-core/platform-core): PDPPREFERENCEORIGIN SHALL default to http://localhost:3000 and PDPPDBPATH SHALL default to /var/lib/pdpp/pdpp.sqlite so SQLite storage and generated credentials land on the mounted data volume. Managed platforms override both per deploy.