fix: persistent dirs for opencode via XDG_*_HOME

fix: HERMES_HOME=/data/.hermes for persistence across restarts

add opencode-ai to image

simplify: remove nginx, code-server with built-in auth on 7860

fix: clear base ENTRYPOINT, use CMD

fix: use official hermes-agent base image

fix: install node via tarball instead of nodesource

fix: add nodejs before npx usage

Initial commit: dev workspace with hermes agent