Case-folded view of a string cell with word-aware case recovery on
write. Read folds to lower (default) or upper; write recovers the
source's per-word case — lookup priority: (1) content match (FIFO
across duplicates); (2) per-position fallback for new content; (3)
native for content beyond the source structure.
Case-folded view of a string cell with word-aware case recovery on write. Read folds to lower (default) or upper; write recovers the source's per-word case — lookup priority: (1) content match (FIFO across duplicates); (2) per-position fallback for new content; (3) native for content beyond the source structure.