source_size_probe decoded every embedded file other than PSD/TIFF/PNG/JPEG
in full just to learn its size. photocraft_codecs::probe_size reads the
size from the same decoders' headers (WebP chunks, the image crate's
GIF/BMP/TGA/ICO/QOI/HDR headers, flat EXR part headers), with the same
limit checks and the EXIF quarter-turn swap, so it agrees with decode
wherever decode succeeds. Deep EXR, AVIF and anything else still decode.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
