- ocr_render.py: extend consumed frontmatter roles skip from page 1 to pages <= 2,
preventing paper_title appearing twice on pre-proof papers
- ocr_document.py: add image/media block promotion in backmatter zone normalization
so raw image blocks become media_asset instead of backmatter_body; this fixes
build_figure_inventory producing 0 matched_figures. Also check seed_role in
_sanitize_reference_zone_boundary since it runs before role resolution
- scripts/dev/ocr_rebuild_paper.py: single-paper rebuild + block_trace regeneration
entry point (will be wired into CLI later)
- tests: boundary protection and completeness check tests
- DW trace regenerated with correct role distribution
