artboard.move with copy and artboard.duplicate now make the copy with one helper: a
new id that can't overflow and a name of its own (`<name> copy`, then `<name> copy 2`…,
so two copies of one artboard no longer share a name). `moved` lists the copies a copy
moved rather than the originals it left. Test it with and without moveArt, and note
Alt-drag in the ROADMAP.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>