The popup has never been audited. It is the primary interface and it is the place a human
approves messages, so it needs to work with a keyboard and a screen reader.

The work: keyboard navigation through every tab and the queue; visible focus states; ARIA
labels on icon-only buttons; contrast at WCAG AA on both themes; aria-live on the queue count
and status dot; prefers-reduced-motion respected.

Files: extension/src/popup/*, extension/src/options/*.

Done when: the queue can be approved end to end with a keyboard alone, axe reports no
criticals, and the PR says what was tested with which screen reader.