A change request's view of all its commits reads and saves viewed marks
on the code host, disabling a checkbox while its mark is saved and every
checkbox when the marks cannot be read; local changes and chosen commits
keep their marks in the browser. The expanded card shows one row per
fact with a glyph and its value: checks open a grouped menu that reruns
failed ones, the review row shows reviewer avatars and requests reviews,
the merge row updates a head behind its base at the displayed head, the
changes row counts unresolved threads, and linked issues take one row.