The outline went around each item's layout box, which is the whole
canvas for texts and images and ignores the turn of rotated abilities
and custom shapes. Each item now marks the shape it draws with an
EditorItemOutline, inside its rotation, and that marker draws the
outline.

Also from review:
- The room lets through any editing message that only takes things
  away, not just a full clear, so ending a drag while a lineup dialog
  stays open cannot be throttled into a stale outline.
- Editing messages stay within the 2048 characters a room from before
  items were relayed reads, leaving items out rather than groups, and
  the room keeps that limit.
- A press off the canvas (a sidebar drag) no longer clears the items
  the user has open.

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