[engine-failure] PROJ-171-quantifying-neural-representation-drift- @ plan: RuntimeError

Automated report (spec 023 / FR-016) — an unexpected engine failure occurred while processing **PROJ-171-quantifying-neural-representation-drift-** at stage `plan`.

```
RuntimeError: LLMReviewer[data_resources]: 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: data_resources\nreviewer_kind: llm\nstage: planned\nartifact_path: projects/PROJ-171-quantifying-neural-representation-drift-/specs/001-quantifying-neural-drift/plan.md\nartifac'
```

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 with the generated review artifact at projects/PROJ-171-quantifying-neural-representation-drift-/specs/001-quantifying-neural-drift/plan.md and trace the parser that raises the reported RuntimeError. Check how review frontmatter handles verdict, concerns, and action_items, then verify that a truncated or contentless review cannot count as acceptance and that the normal retry can proceed.

Written by the indexing model from the issue text.