[engine-failure] PROJ-821-llmxive-follow-up-extending-training-lon @ tasks: RuntimeError

Automated report (spec 023 / FR-016) — an unexpected engine failure occurred while processing **PROJ-821-llmxive-follow-up-extending-training-lon** at stage `tasks`.

```
RuntimeError: LLMReviewer[ordering]: 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: ordering\nreviewer_kind: llm\nstage: fleshed_out_complete\nartifact_path: projects/PROJ-821-llmxive-follow-up-extending-training-lon/specs/001-llmxive-follow-up-extending-train'
```

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 locating the Python LLMReviewer ordering path that parses review frontmatter during the tasks stage, then reproduce the PROJ-821 retry using the captured truncated YAML. Trace how contentless reviews and the reported RuntimeError are handled, and identify the relevant regression coverage. Done means the underlying engine failure is fixed without allowing an incomplete review to count as acceptance.

Written by the indexing model from the issue text.