Support running the web UI alongside self-hosted Honcho docker-compose #31

Requested by u/random-maakan on Reddit: https://www.reddit.com/r/hermesagent/comments/1t0w8fz/comment/onwzuae/

Any plans for running it on Docker? Should be an easy addition to self hosted Honcho docker compose.

Context

The web SPA can now be containerized (see #23 — multi-stage Dockerfile + nginx). This issue tracks the next step the request implies: a turnkey way to run OpenConcho as part of a self-hosted Honcho docker-compose stack, sitting next to the Honcho service.

Scope

• A documented docker-compose snippet (or a compose service) that runs the OpenConcho web image alongside Honcho.
• Resolve the CORS story in that topology — either point the UI at Honcho's origin with CORS configured, or use the same-origin nginx reverse-proxy block shipped (commented) in feat(docker): containerized web build + CORS guidance #23. Same-origin proxy needs the Settings form to accept a relative base URL (currently z.string().url() requires absolute) — see feat(docker): containerized web build + CORS guidance #23 follow-up.

Open question (from maintainer reply)

In what context is Docker needed — the web app itself? The desktop builds are native and don't need Docker; the container exists today mainly to sidestep CORS. Requirements detail welcome.

Filed on behalf of the reporter to capture the feedback; thank you u/random-maakan.