Function toggleHost

frontend/src/components/timeline/NetworkPanel.tsx:481–491

(host: string)

    : null;

  const toggleHost = (host: string) => {
    setExpandedHosts((prev) => {
      const next = new Set(prev);
      if (next.has(host)) {
        next.delete(host);
      } else {
        next.add(host);
      }
      return next;
    });
  };

  // Auto-expand all hosts on first render
  useEffect(() => {