Description

If for some reason I switch to interactive mode, there is an inconsistency in the way environment variables are picked up. NEMOCLAW_SANDBOX_NAME is never used while NEMOCLAW_ENDPOINT_URL is pre-populated.
It would be good to use all variables present in the environment as defaults that we can simply validate when in interactive mode.

NEMOCLAW_SANDBOX_NAMEis given as an example. There may be others.

Reproduction Steps

1. export NEMOCLAW_SANDBOX_NAME=mythos
2. nemoclaw onboard

Environment

Hardware: GB10
OS: Ubuntu 24.04 LTS
OpenShell 0.0.36
NemoClaw 0.0.34

Debug Output

Logs

Checklist

• I confirmed this bug is reproducible
• I searched existing issues and this is not a duplicate