[engine-failure] PROJ-1032-llmxive-follow-up-extending-https-arxiv @ spec: RuntimeError

Automated report (spec 023 / FR-016) — an unexpected engine failure occurred while processing **PROJ-1032-llmxive-follow-up-extending-https-arxiv** at stage `spec`.

```
RuntimeError: LLMReviewer[scope]: review frontmatter has neither `verdict:` nor `concerns:`/`action_items:` — a contentless/truncated review MUST NOT count as acceptance (false-convergence guard). First 200 chars: '```yaml\n---\nreviewer_name: rq_validity\nreviewer_kind: llm\nstage: clarified\nartifact_path: projects/PROJ-1032-llmxive-follow-up-extending-https-arxiv/specs/001-llmxive-follow-up-extending-https-arxiv/s'
```

The project remains schedulable; it will retry on its normal cadence and recover once the underlying defect is fixed. Closing this issue does not require any project-state change.

Start by tracing the LLMReviewer[scope] handling at stage `spec` for the artifact under `projects/PROJ-1032-llmxive-follow-up-extending-https-arxiv/specs/001-llmxive-follow-up-extending-https-arxiv/`. Reproduce the reported RuntimeError and inspect how review frontmatter is parsed. Done means a contentless or truncated review cannot count as acceptance and the normal retry can recover, without changing project state.

Written by the indexing model from the issue text.