photo.exif() and backup-metadata --exif read EXIF with exifreader,
which reads JPEG, HEIC/HEIF, AVIF, PNG and WebP, so a HEIC original or
a live photo's HEIC image gets its EXIF. exifreader replaces
exif-reader and the hand-written JPEG segment scan. PhotoExif is
unchanged. The exif field of backup-metadata --exif is now
exifreader's tag output, and exifRaw holds the whole EXIF block it
could not read. Tests use a real 933-byte HEIC fixture, test/exif.heic,
whose recipe is in test/exif-heic.ts.
Model: opus-5-5
