Extends layoutStore with previewSession/commitPreview, mirroring
multiview.ts's preview controller: a throwaway tab for a session no pane
holds, byte-for-byte restore on end, and every real layout-changing action
drops an active preview first. Never schedules a save while a preview is up.
Adds usePreview, wrapping the store actions with previewSchedule.ts's
120ms leading-edge throttle, plus a touch guard and an immediate `end()`
for real changes. MultiView/TabBar render the preview hue on the pane
titlebar, canvas ring/chip, and the throwaway tab (dashed, unclickable).
Closes#249: layoutStore.ts wraps the existing layout.ts tree model
in Zustand, persisting to localStorage on a 400ms debounce and adding
boot reconciliation to prune leaves for sessions no longer live.
MultiView/TabBar/PaneContainer/PaneTitle render tabs, nested splits
with draggable dividers, drag-and-drop tab reordering, and dispatch
each pane to TerminalPane or StructuredPane by session view.
Preview mode (#251) and sidebar drag-to-dock stay out of scope here.
Ports events.ts's CatalogStore and connections.ts's ConnectionPool to
Zustand stores (src/stores/catalogStore.ts, connectionStore.ts) built
via factory functions so tests can inject fake sockets/schedulers, same
as the originals. Reconnect/backoff schedule, the 6-max-parked LRU, and
the #140 view-reconciliation race handling all carry over unchanged.
The vanilla events.ts/connections.ts stay in place for the current app;
this is prep for the React port (#241).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Miguel Palhas