Sandbox creation fails during onboarding #949

Description

I'm running nemoclaw onboard within an Ubuntu 24 WSL instance. During sandbox creation (Step 7) the image builds fine but fails to properly start up. The nemoclaw-start script fails at line 19:

ulimit -Hu 512 || {
  echo "[SECURITY] Failed to set hard nproc limit" >&2
  exit 1
}
ulimit -Su 512 || {
  echo "[SECURITY] Failed to set hard nproc limit" >&2
  exit 1
}

The hard limit cannot be lowered below the soft limit. These two commands need to be swapped otherwise you get the following error:

bash: line 1: ulimit: max user processes: cannot modify limit: Invalid argument

Reproduction Steps

1. Run nemoclaw onboard
2. Select any options until step 5 when the sandbox is being created
3. Note the failure with the message:

   /usr/local/bin/nemoclaw-start: line 19: ulimit: max user processes: cannot modify limit: Invalid argument
   [SECURITY] Failed to set hard nproc limit
   Error:   × ssh exited with status exit status: 1
     Try:  openshell sandbox list        # check gateway state
     Try:  nemoclaw onboard              # retry from scratch
   

Environment

• OS: Ubuntu 24.04 via WSLv2
• Node: v20.20.2
• Docker: 29.3.0, build 5927d80
• NemoClaw: v0.1.0 (commit 2804eae)

Debug Output

Logs

Checklist

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