Reserve side and bottom decoration borders for normal windows and draw a rounded decoration frame so windows match the convergence workspace shape. Add static guards for the decoration and existing workspace-frame corner geometry.
Keep one layout per output and virtual desktop. Move new windows to another existing desktop when the current page is full.
When a user moves a window onto a full page, replace the last focused window on that page and send it back to the source desktop. Use stable slot swaps instead of insert splits so the layout shape does not change during moves.