Feature: Keyboard Controls

Make it possible to control the entire website using the keyboard.
If the user is not in a race or otherwise typing into a textbox, etc. (see if checking that if possible...), typing any character should open a textbox.
Of any button are link, containing the typed text, the best match should be highlighted.

Enter -> Select -> Click
Tab -> Select next best matching element

Add a highlight box of some sort around the selected element.

No files, tests, or entry points are identified. Start by locating the extension's keyboard handling and interactive-element selection, then define behavior for typing, Tab, and Enter without disrupting text input. Done means the requested keyboard navigation and a visible highlight work across the website.

Written by the indexing model from the issue text.