feat: file manager as a workspace pane, side by side with terminals; zip and delete of the selection as icons

internal/server/web/static/workspace.js

@@ -305,7 +305,7 @@
     const src = drag.kind === 'tab' ? drag.obj.el : drag.obj.el.querySelector('.pane-head');
     const g = document.createElement('div');
     g.className = 'drag-ghost ' + drag.kind;
-    g.textContent = drag.kind === 'tab' ? tabTitle(drag.obj) : drag.obj.agent.user + '@' + drag.obj.agent.host;
+    g.textContent = drag.kind === 'tab' ? tabTitle(drag.obj) : (drag.obj.tooltip ? drag.obj.tooltip() : drag.obj.title());
     document.body.appendChild(g);
     drag.ghost = g;
     drag.src = src;
@@ -409,7 +409,7 @@
       renderTab(t);
       layout(t, true);
       updateMode();
-      s.term.focus();
+      s.focus();
     } else if (d.kind === 'pane' && tg.kind === 'strip') {
       const s = d.obj, from = tabOf(s), ref = tg.others[tg.index];
       takePane(from, s);