On iPad and tablets, the main navigation menu is rendered as a
responsive Bootstrap offcanvas drawer (`#navbarSupportedContent.offcanvas-lg`).
When users tapped 'Sign in' in the drawer, the auth modal opened while the
offcanvas remained open in the DOM, allowing Bootstrap's active FocusTrap
on the offcanvas to intercept focusin events on document and steal focus
away from the modal inputs, preventing clicking or typing on iPadOS.
Update `closeOpenOffcanvases` in `Modal.jsx` and `RecordDialog.jsx` to
match all open offcanvases including responsive ones
(`.offcanvas.show, [class*="offcanvas-"].show`) and closest offcanvas
containers, invoke it when auth dialog triggers are clicked in
`AuthDialog.jsx`, restore focus correctly when the modal closes, and add
accompanying tests.
Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>
