The sentinel div (h-4) added extra space below the pagination bar
on pages with a next page, making the pagination bar appear taller
than on the last page. Since infinite scroll only runs on mobile,
hide the sentinel on desktop with md:hidden.
Add search_header macro with Datastar-driven live search and debounced
input. Move pagination controls from above to below tables. Add
pagination-controls class for mobile hiding. Add infinite scroll
sentinel divs and data attributes to all list partials.
