Flutter DevTools Extension not appearing in DevTools UI despite correct setup

Question

I'm building a custom Flutter DevTools extension using the devtools_extensions package with Flutter 3.32.6 and Dart 3.8.1. I created the extension project using flutter create --template devtools_extension my_new_tool, and I’m serving it via webdev serve web:8080. The extension builds and runs fine as a standalone Flutter web app. In main.dart, I'm using DevToolsExtension(child: FooTab()) as documented. I then launch Flutter DevTools using dart devtools, and try accessing the extension by appending ?ext=http://localhost:8080 to the DevTools URL. Despite this, my extension does not appear as a new tab in the DevTools UI. There are no console errors, and I’ve confirmed the app serves correctly on port 8080. I also ensured DevTools was started after the extension server. What might I be missing to get my extension to show up in the DevTools interface?