[Brev][Onboard] Onboarding progress percentage stuck at 0% despite completing successfully

## Description

On Sep 11, 2026, browser-based onboarding on a fresh NemoClaw Brev Launchable displayed 0% for the entire build even though the activity log continued to emit new step output and onboarding completed successfully. The stale percentage makes an active setup look hung.

Platform scope: Brev Launchable only.
Reproducibility: Observed during the successful OpenClaw browser onboarding in this run; a dedicated repeat focused only on the percentage was not performed.
OpenShell issue: No functional OpenShell failure was observed.

## Environment

```text
Device: Brev Launchable, Free n2d-standard-4 CPU instance
OS: Ubuntu 22.04.5 LTS (same Launchable image; captured on a companion instance)
Architecture: x86_64 (same Launchable image; captured on a companion instance)
Node.js: v22.23.2 (same Launchable image; captured on a companion instance)
npm: 10.9.8 (same Launchable image; captured on a companion instance)
Docker: 29.1.3 (same Launchable image; captured on a companion instance)
OpenShell CLI: 0.0.106 (same Launchable image; captured on a companion instance)
NemoClaw: Not captured on the affected onboarding instance before cleanup; the same Daily Tag Launchable was separately verified as v0.0.122 on a fresh companion instance
OpenClaw: 2026.7.1
Provider: OpenRouter
Model: nvidia/nemotron-3-ultra-550b-a55b
```

## Steps to Reproduce

1. Open the NemoClaw Daily Tag Brev Launchable deployment page.
2. Select the Free entitlement and deploy a fresh instance with the default compute settings.
3. Wait until Brev reports RUNNING, build COMPLETED, shell READY, and health HEALTHY.
4. Open the shareable URL linked to port 80 and complete NVIDIA SSO if prompted.
5. Select "SET UP IN THIS BROWSER".
6. Select OpenClaw, OpenRouter, and model `nvidia/nemotron-3-ultra-550b-a55b`.
7. Start agent creation.
8. On the "IN PROGRESS / BUILDING YOUR AGENT" page, watch the activity log produce new output while also watching the displayed PROGRESS percentage.
9. Continue observing the percentage until onboarding completes and the dashboard opens.

## Expected Result

The progress percentage should advance as onboarding completes its steps and reach a completed state when the dashboard becomes available.

## Actual Result

```text
IN PROGRESS
BUILDING YOUR AGENT
PROGRESS
0%
```

The activity log continued updating and onboarding completed successfully, but the displayed percentage remained at 0% and never advanced.

## Impact

Users cannot distinguish an active onboarding run from a stalled run by using the progress indicator, which can lead to unnecessary refreshes or duplicate setup attempts.

## Related Bugs / not duplicate of

A separate, still-open GitHub issue about browser-refresh losing onboarding progress state happens to show this same "0%" reading in its own before-refresh evidence, as a side detail unrelated to that issue's main subject (refresh losing state) - corroborating this is a real, observable UI state rather than a one-off render glitch, though that other issue does not track this specific stuck-percentage symptom itself.

## Logs

```text
Browser-visible state:
IN PROGRESS
BUILDING YOUR AGENT
PROGRESS
0%
```

The activity log continued to update with real setup output until successful completion.

Start by reproducing browser onboarding on a fresh Brev Launchable using the steps and environment recorded in the issue. Trace the onboarding progress display alongside the updating activity log; done means the percentage advances during setup and reaches a completed state when the dashboard opens.

Written by the indexing model from the issue text.