[aw] CI Outer-Loop Failure Scanner failed

### Workflow Failure

**Workflow:** [CI Outer-Loop Failure Scanner](https://github.com/dotnet/runtime/blob/main/.github/workflows/ci-failure-scan.md)
**Branch:** main
**Run:** https://github.com/dotnet/runtime/actions/runs/34729903269

> [!WARNING]
> **Engine Failure**: The `copilot` engine terminated unexpectedly.

**Last agent output:**
```
Check your COPILOT_PROVIDER_API_KEY or COPILOT_PROVIDER_BEARER_TOKEN.
Changes +0 -0
Duration 19m 22s
Tokens ↑ 14.3m (14.1m cached) • ↓ 73.3k
Resume copilot --resume=b24b6700-764e-4a36-8240-47bfa8341473
Authentication failed with provider at http://172.30.0.30:10002 (HTTP 403).
Check your COPILOT_PROVIDER_API_KEY or COPILOT_PROVIDER_BEARER_TOKEN.
Changes +0 -0
Duration 0s
Resume copilot --resume=b0b57c51-5fac-469e-8ba2-9ae20eaed5a7
```

### Action Required

**Assign this issue to an agent** to debug and fix the issue.

Debug with any coding agent

Use this prompt with any coding agent (GitHub Copilot, Claude, Gemini, etc.):

````
Debug the agentic workflow failure using https://raw.githubusercontent.com/github/gh-aw/main/debug.md

The failed workflow run is at https://github.com/dotnet/runtime/actions/runs/34729903269
````

Manually invoke the agent

Debug this workflow failure using your favorite Agent CLI and the `agentic-workflows` prompt.

- Start your agent
- Load the `agentic-workflows` skill from `.github/skills/agentic-workflows/SKILL.md` or
- Type `debug the agentic workflow ci-failure-scan failure in https://github.com/dotnet/runtime/actions/runs/34729903269`

> [!TIP]
>
> Stop reporting this workflow as a failure
>
> To stop a workflow from creating failure issues, set `report-failure-as-issue: false` in its frontmatter:
> ```yaml
> safe-outputs:
> report-failure-as-issue: false
> ```
>
>

> Generated from [CI Outer-Loop Failure Scanner](https://github.com/dotnet/runtime/actions/runs/34729903269) · 996.9 AIC · [◷](https://github.com/search?q=repo%3Adotnet%2Fruntime+is%3Aissue+%22gh-aw-workflow-id%3A+ci-failure-scan%22&type=issues)

Start with .github/workflows/ci-failure-scan.md and the failed run at https://github.com/dotnet/runtime/actions/runs/34729903269; review the agentic-workflows skill for the scanner's debugging process. Investigate the HTTP 403 authentication failure for the copilot engine, then rerun the workflow to confirm the scanner completes without an engine failure.

Written by the indexing model from the issue text.