feat: workspace lives in the terminal view and keeps its sessions across pages; terminal panes split out

internal/server/web/static/app.js

@@ -128,6 +128,9 @@
   function start() {
     document.querySelectorAll('main#app > .view').forEach(mount);
     show({dashboard: 'machines', settings: 'settings'}[$('main#app').dataset.view] || 'terminal');
+    // /agents/{id}/terminal or /files: that pane, at once.
+    const o = window.APP && window.APP.open;
+    if (o && window.Workspace) window.Workspace.open(o.kind, o.agent);
   }
   window.App = {go, load, register, put, start, scope};
 })();