[engine-failure] PROJ-354-investigating-the-correlation-between-gu @ tasks: RuntimeError

Automated report (spec 023 / FR-016) — an unexpected engine failure occurred while processing **PROJ-354-investigating-the-correlation-between-gu** at stage `tasks`.

```
RuntimeError: LLMReviewer[executability]: 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: task_executability\nreviewer_kind: llm\nstage: tasks\nartifact_path: projects/PROJ-354-investigating-the-correlation-between-gu/specs/001-investigating-the-correlation-between-'
```

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[executability] handling for the review artifact under projects/PROJ-354-investigating-the-correlation-between-gu/specs/001-investigating-the-correlation-between-. Inspect how the tasks-stage frontmatter is parsed when it has neither verdict nor concerns/action_items. Done means the underlying defect no longer produces this engine failure while contentless reviews remain rejected.

Written by the indexing model from the issue text.