Decoders now report what the decoded image doesn't show in a new
`Image::warnings` (`photocraft_codecs::DecodeWarning`), and `image_to_document`
turns them into import warnings, so they reach `photocraft-cli info` /
`convert` stderr, `doc.open` over MCP and serve, and the app's open notice
through the existing import-warnings path.
* #523: APNG (acTL frames, plus a default image outside the animation),
animated GIF (image descriptors counted by walking the blocks), animated
WebP and multi-page TIFF (IFDs walked without decoding; reduced-resolution
copies and transparency masks are not pages) say "only the first of N
frames/pages was imported". Single images stay quiet; the kept frame's
pixels are unchanged.
* #518: a JPEG whose data runs out before its end-of-image marker (marker
segments skipped by length, scan data by byte stuffing) still decodes
leniently but warns "JPEG data ends early (the file is truncated or
damaged); part of the image is missing". A JPEG that ends before any scan
data is an error.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
