- The entry size cap is figcraft_doc::ImageData::MAX_BYTES (256 MiB), the
cap the .fig, .sketch and REST importers already read images with (now
one constant), instead of 32 MiB: an imported image larger than 32 MiB
made the document unjoinable and its server snapshot unrestorable.
- History written before the checks (a restored or joined snapshot, a
replayed server log, a file published to a server) applies without the
image entries they refuse (docprops::without_refused_images), instead of
the file not opening or a restart dropping every edit after the image.
- A key that already holds an image can't be given other bytes: producers
key images by their bytes (the REST importer's placeholder keys always
hold the same picture), and merge treats a key's image as never
changing.
- REST import: an unresolved imageRef shaped like a content hash shares
the rest-image-missing placeholder (the placeholder's bytes don't hash to
it); ImageData::claims_content_hash is shared with collab.
- Tests: collab image_tests (4 new, size test uses a small cap), format
image_tests (1 new).
- Docs: collab-protocol.md, collaboration-parity.md, file-format-parity.md.