The earlier search slot in the sidebar toolbar shared a glass group with
New chat. UIKit moved the search into the detail column's vertical bar
while New chat stayed in the sidebar, and their shared glass stretched
between the two positions into the oval across the detail column.

- A primary column's toolbar search is held to horizontal bars, the axis
  behavior UIKit provides for items that must stay out of the vertical
  bar.
- A fixed space gives search its own glass group apart from New chat.
- Folded, search keeps UIKit's placement because the workspace tab bar
  owns the bottom of the vertical bar there.

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