* test(e2e): record mixed-version, two-client and phone layout baselines on main (P3)
* test(e2e): P3 review fixes: reconnect and I/O proof, restart order bounds, Linux-only baselines
* test(e2e): re-record Linux phone and serve-restart baselines
* test(e2e): P3: echo drawn in the desktop pane; bound the group selection after restart
* test(e2e): re-record serve-restart group selection
* test(e2e): name P3 baseline helpers for what they record