Fix merit badge requirement list nesting

[dasevilla]

Summary

• reparent contiguous numbered topic and option lists under the alphabetic action or named option that governs them
• preserve source IDs, content, resources, action/container semantics, and recompute paths from the repaired tree
• warn when archive validation detects likely governed numeric siblings that remain flattened
• document the semantic JSON hierarchy behavior and add focused regression coverage

Validation

• make check
• uv run python -m unittest discover -s tests -v (26 tests)
• corpus replay: 23 groups / 136 leaves repaired across 18 badges, with zero governed groups remaining
• verified payload preservation, unique paths, consistent container flags, and unchanged node_kind/requires_response metadata
• replayed live browser-captured markup for Emergency Preparedness, Disabilities Awareness, and Camping through the production extractor and semantic processor