The base docker-compose.yml already mounts ./notebooks:/app/notebooks.
The named Docker volume was shadowing it in prod, preventing example
notebooks from being visible. Bind mount ensures examples ship with
the repo and user notebooks persist on the host filesystem.
Bind mounts inherit host UID which conflicts with the container's
non-root user. Named volumes are initialized from the image layer,
preserving the chown from the Dockerfile.
Update frontend Dockerfile prod stage from Caddy static to Node.js
running Astro SSR server. Configure caddy-docker-proxy labels to
route /api/* to backend and everything else to frontend on the same
domain. Support empty PUBLIC_API_URL for same-origin API calls.
