- The compound file is read with craft-cfb (bounded directory, streams refused
above 1 GiB before anything is allocated), in place of the cfb crate and
WordCraft's cfb_guard precheck; an oversized stream is DocbinError::Limit.
- 8-bit text uses craft-codepage in place of wordcraft_doc::encoding.
- wordcraft-doc is craft-wordmodel; wordcraft-geom's helpers are its geom.
The tests keep building their files with the cfb crate (a dev-dependency), so
craft-cfb's reader is checked against another implementation's writer. The
repeating-DIFAT regression is craft-cfb's own; the guard asserts in the
valid-files test go with the guard.