Panes were keyed by slot alone, so slot 0 of the next workspace reused the
previous one's pane: every switch disposed its terminals and attached new
ones (a WebSocket each, the whole screen replayed). The live panes of the
last 4 workspaces left now stay mounted as hidden siblings in the same
grid, keyed by paneKey (lane x 10 + slot), so going back is instant.
Measured on 3 workspaces x 2-3 shell panes, switching back to one already
opened: script 210 -> 52 ms, main thread 370 -> 120 ms, long tasks
120 -> 0 ms, terminal re-attaches 2-3 -> 0.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
nntrivi2001
d72a255294