The add of a page "+" copied here now names every item and lineup group
of its copy. A write cut short can leave the add and only some of them on
disk, each readable; such an add and the items that are there wait in
attention, saying the copy didn't finish saving, instead of being sent as
a smaller copy. An item removed here on purpose leaves the list first.

DrawnPage.opens now counts a page made here, so next/previous, the delete
fallback and opening a strategy reach it. Copy-to-page still needs its
target on the server.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>