The archive half of FigCraft's Penpot import and export
(crates/format/src/penpot.rs and penpot/embedded_fonts.rs at 3b9bf8c9):
ZIP validation, the manifest, bounded JSON members with the shared byte
and value budgets, pages, page shapes, media objects, font signatures,
and the archive writer. Members are handed out as the JSON the file
holds; mapping shapes stays in the app.
Duplicate member names are now refused: the ZIP reader keeps one member
per name, so the per-name check FigCraft has never fires. The directory's
own member count is compared instead.
