Add blob-sanitize.mjs with stripBlobMetadata() (canvas re-encode for
JPEG/PNG/WebP, byte-level PDF /Author stripper, pass-through for audio/video)
and hasImageMetadata() (lightweight EXIF/XMP detection). Wire into
uploadToServer() before calculateSHA256 so the client-signed hash commits
to cleaned bytes (preserves BUD-01 content addressing). Add skipSanitize
opt-out for mirror/verbatim uploads. On 415 + X-Reason: exif_detected,
retry once with forced stricter re-encode. Update post-composer status
text and surface metadata-rejection errors.
See ~/lt/metadata_stripping/plans/blob-metadata-stripping.md (Part 1).
Laan Tungir
d1f537fcae