module-source-coverage

Use when a tutorial module plan exists and the run needs an auditable module-to-source grounding file before prose. **Trigger**: module coverage, source coverage, tutorial grounding, 模块覆盖, 来源覆盖. **Use when**: `source-tutorial` 的 C2，已有 `outline/module_plan.yml`，需要确认每个模块都能回指到 sources。 **Skip if**: mod