Enhance text normalization by incorporating font ascent and descent data to more accurately position glyphs, especially for decorative initials. Update merge logic to better detect line membership using vertical overlap, ensuring drop caps and overlapping glyphs are merged correctly. Extend tests to cover these layout scenarios.
Update normalizeTextItemsForLayout to correctly apply viewport transforms,
including non-zero page origins, ensuring accurate mapping of PDF text items
to top-left coordinates. Refactor runLayoutModel to implement a custom order
sequence builder for layout regions using model order logits, improving
region ordering consistency with model semantics. Update related tests to
cover viewport transform edge cases.
