[engine-failure] PROJ-208-statistical-analysis-of-publicly-availab @ tasks: RuntimeError

Automated report (spec 023 / FR-016) — an unexpected engine failure occurred while processing **PROJ-208-statistical-analysis-of-publicly-availab** 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: rq_validity\nreviewer_kind: llm\nstage: tasks\nartifact_path: projects/PROJ-208-statistical-analysis-of-publicly-availab/specs/001-statistical-analysis-of-publicly-availab/task'
```

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 at the LLMReviewer[executability] entry point while reproducing processing at the `tasks` stage for the artifact under projects/PROJ-208-statistical-analysis-of-publicly-availab/specs/001-statistical-analysis-of-publicly-availab/task. Trace how the review frontmatter is handled when it contains neither `verdict:` nor `concerns:`/`action_items:`. Done means a contentless or truncated review cannot count as acceptance and the normal retry can recover.

Written by the indexing model from the issue text.