Dockerfile best practice: specify non-root USER in custom tool example Dockerfile

Context

The Dockerfile at examples/02_remote_agent_server/06_custom_tool/Dockerfile does not currently specify a USER directive, so the container runs as root by default.

Best practice

It is a Docker best practice to run containers as a non-root user. Adding a USER directive with a non-root user avoids unnecessary privilege and follows community conventions for well-formed Dockerfiles.

Suggested change

Add a non-root user to the Dockerfile, e.g.:

RUN useradd -m appuser
USER appuser

Or use an existing non-root user if one is already created in the base image.

Acceptance criteria

• Dockerfile includes a USER directive with a non-root user
• Container still builds and runs correctly

Start with examples/02_remote_agent_server/06_custom_tool/Dockerfile and inspect the base image for any existing non-root user. Add a non-root USER directive, then build and run the container to confirm it works and the acceptance criteria are met.