OptionalautoWhen focusId is set, take focus on mount if no other focusable
currently holds it.
OptionalfocusDefault true. When false, does not consume keystrokes (active tab styling
still renders). Ignored when focusId is set.
OptionalfocusRegister this strip with useFocus(id) so the surrounding
<FocusProvider> can route Tab / Shift+Tab cycling through it.
Called when the user activates a different tab via arrow / Home / End.
Currently active tab key. Controlled — pair with
onChange.