Pastes over 4000 chars or 100 lines attach as a timestamped pasted-text-*.md in
the upload tray instead of flooding the composer. Image-paste path unchanged; an
oversize paste that exceeds MAX_UPLOAD_BYTES falls through to a normal inline
paste so nothing is lost.
Co-authored-by: santastabber <204424800+santastabber@users.noreply.github.com>
