Treat stacked upright identifiers as a layout problem, separately from text rotation

Treat stacked upright identifiers as a layout problem, separately from text rotation. A 0/180 text-line classifier cannot resolve 90/270-degree text, and rotating a vertical stack turns otherwise upright glyphs sideways. When adding rotation candidates, do not assume the candidate with the highest mean OCR confidence preserves the whole identifier: omitting a difficult middle glyph can raise that mean. Validate any stack-to-row reflow on development crops, freeze its admission and selection rules before held-out scoring, and report exact identifier accuracy on both reference crops and detector crops. This applies to narrow identifier ROIs; segmentation/reflow can itself damage slanted, touching, or genuinely sideways text, and OCR confidence does not prove subject association.