[macOS/WSL2][Onboard][Regression] OpenShell dashboard forward times out and blocks sandbox onboarding

## Description

NemoClaw v0.0.126 onboarding repeatedly fails after sandbox creation on both Apple Silicon macOS and WSL2 because the OpenShell dashboard forward operation times out. This blocks unrelated product flows before their assertions can run.

The failure reproduced across independent macOS shards and independent WSL2 onboarding groups. Harness cleanup and container-runtime preflight passed between attempts.

## Environment

### macOS

- NemoClaw: v0.0.126
- macOS: 26.5 (Darwin 25.5.0), arm64
- Host: Apple M4 Max
- Container runtime: Colima / Docker Engine 29.x
- OpenShell CLI: 0.0.116

### WSL2

- NemoClaw: v0.0.126
- Architecture: x86_64
- Container runtime: Docker Desktop / Docker Engine 29.x
- OpenShell CLI: 0.0.116

## Steps to reproduce

1. Start from a clean macOS or WSL2 host with the container runtime healthy.
2. Install NemoClaw v0.0.126.
3. Onboard a Hermes or OpenClaw sandbox with a valid inference configuration.
4. Wait for sandbox creation and dashboard forward allocation.

## Expected result

The owned OpenShell dashboard forward is established and onboarding completes.

## Actual result

```text
Cannot allocate dashboard port: The OpenShell forward operation timed out.
```

The same failure recurs after cleanup in multiple independent onboarding attempts. On WSL2 it also occurs with a Windows-host Ollama route, which rules out a single cloud-provider dependency as the cause of the dashboard-forward failure.

## Reproducibility

Reproduced repeatedly on macOS and WSL2 with separate cleanups and onboarding attempts. The failure blocks otherwise unrelated install, onboarding, sandbox-lifecycle, CLI, and security-validation flows before trustworthy assertions can complete.

## Regression and duplicate check

Related closed issue #6099 reported a macOS/Colima forward tracking timeout on older releases. v0.0.126 shows the failure again with OpenShell 0.0.116 and additionally reproduces on WSL2. No exact open issue was found.

No source files or tests are named. Start at the NemoClaw onboarding path after sandbox creation, focusing on the OpenShell dashboard forward allocation that reports the timeout; reproduce it on macOS and WSL2 with the stated runtimes. Done means the owned dashboard forward is established and onboarding completes without the timeout.

Written by the indexing model from the issue text.