2ae4adfde4
Design for replacing the two-scalar layout (pty_pct + roster_width) with a binary space-partition pane tree so every pane is resizable on both axes, fixing the "only roster width adjusts" limitation. Rolls a small in-repo tree (no new dep) and drives the PTY grid from the terminal pane's actual Rect. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>