takahashi-akari/docker-ubuntu-desktop — reverse-engineered prompt

Build me a Docker image that starts a full Ubuntu desktop and lets me use it from my web browser through VNC. I want to run one Docker command, open localhost on port 6080, go to vnc.html, and see the Ubuntu desktop in the browser like the screenshot suggests.

Keep it simple and focused. Include the Dockerfile and a clear README with how to run it, how to build it locally, how to pull or publish the image, and the browser URLs to try with http and https. It should work on linux amd64, and the container should expose the right port for browser access.

Please make the repo clean and easy for someone who just wants a disposable Ubuntu desktop in Docker. Add a license file too.