The console splits into up to four panes: a binary split tree of tmux
slots (client/src/lib/paneLayout.ts) drawn by PaneGrid.tsx, every pane an
absolutely placed sibling keyed by slot so splitting, swapping, resizing
or closing never remounts a live terminal. Ctrl/Cmd+click on a tab, a +
item or a sidebar session row opens it beside the focused pane (router
state, never the URL); a pane header drags onto another pane's edge to
split there or onto its middle to swap, picks another live session,
splits right/down (a not-shown session or a new terminal), or closes the
pane only. Dividers drag or take arrow keys. ?run= is the focused pane:
every layout change goes through change(), which pushes the URL with
focusOnly instead of an effect watching the focus (that ping-ponged with
open requests). The layout is kept per workspace in localStorage.
Only the focused pane's terminal takes the keyboard when it appears, and
the keyboard follows a focus change. A pane closes when its terminal
reports the exit; the run list prunes only a remembered layout on a
workspace's first read and a just-opened slot that never got listed, so
one empty read cannot wipe a split. A run ending on the home or a replay
closes its pane without leaving the page.
The session view now fills the page edge to edge: no page padding, the
tab bar and the right panel's activity bar one h-10 strip, and the tab
bar, pane headers and right panel on the sidebar/status bar colour
(surface-1) around terminals on the page colour.
