hacess/chrome-extension-manifestv3-screenshot — reverse-engineered prompt

Build me a very simple Chrome extension for the current extension format that lets me take a screenshot of the page I am looking at. I want a small popup with a clear button that says something like Capture Screenshot, and when I click it, it should grab the visible part of the active tab and show the image right inside the popup right away.

Please keep the interface clean and beginner friendly, nothing fancy, just something that works reliably and is easy to understand. It should request only the permissions it actually needs, and it should be ready to test by loading it as an unpacked extension in Chrome. If there are any browser limitations, just handle them in a sensible way and show a simple message instead of breaking.

Use plain JavaScript, HTML, and the normal Chrome extension files. If anything about the current Chrome extension rules has changed, look up the latest docs and make it work with the current setup.