[engine-failure] PROJ-982-llmxive-follow-up-extending-dopd-dual-on @ tasks: RuntimeError

Automated report (spec 023 / FR-016) — an unexpected engine failure occurred while processing **PROJ-982-llmxive-follow-up-extending-dopd-dual-on** 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-982-llmxive-follow-up-extending-dopd-dual-on/specs/001-llmxive-follow-up-extending-dopd-dual-on/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 by tracing the LLMReviewer executability check at the tasks stage and inspect the review frontmatter for the referenced PROJ-982 artifact. Reproduce the RuntimeError with the truncated or contentless review, then confirm the underlying defect is fixed when valid reviews are accepted and invalid reviews remain rejected without changing project state.

Written by the indexing model from the issue text.