The agent could reveal single panes (focus_pane) but had no way to arrange
the workspace as one act. apply_layout closes that gap: a desktop_ui tool
that emits layout.apply over the existing bridge, resolved in the renderer
against the layouts contribution registry — the same list the layout picker
reads — so core presets (default/focus/terminal-deck/quad), plugin presets,
and user-saved presets are all addressable by id. Active session only, same
as pane.reveal: a background turn never rearranges the user's desktop.
Brooklyn Nicholson