LineUpLinkChange recorded removed images without their places and put
them back after the survivors, so [A, B, C], remove A, undo gave
[B, C, A]; order drives the lineup carousel and the panel thumbnail.

Each image a change adds (either direction) now carries the ids of the
images that followed it and are not being added themselves. Writing the
change inserts it before the first of those still present, appending only
when none are, so runs of removed images come back in order and an image
a teammate added in between stays where they put it.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>