Gateway page: live-page instructions (layout, audio, rename, group names, maximise); portal: maximise button per tab bar

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

live/src/GroupActions.jsx

@@ -0,0 +1,16 @@
+import React, { useEffect, useState } from 'react'
+
+// Right end of every tab bar: maximise / restore this group.
+export default function GroupActions({ api, containerApi }) {
+  const [max, setMax] = useState(() => api.isMaximized())
+  useEffect(() => {
+    const d = containerApi.onDidMaximizedGroupChange?.(() => setMax(api.isMaximized()))
+    return () => d?.dispose?.()
+  }, [api, containerApi])
+  const toggle = e => { e.stopPropagation(); if (api.isMaximized()) api.exitMaximized(); else api.maximize(); setMax(api.isMaximized()) }
+  return (
+    <div className="groupactions" onPointerDown={e => e.stopPropagation()}>
+      <button className="gbtn" onClick={toggle} title={max ? 'restore' : 'maximise this window'}>{max ? '🗗' : '⛶'}</button>
+    </div>
+  )
+}