Six small UI polish improvements

Tap targets grew on the date picker's prev/next buttons and the search box's clear button, the EHS MIT lists page got a back-to-top shortcut, the admin extraction page shows a loading skeleton instead of a blank screen, a screen reader now hears whether the MCP revoked-tokens list is expanded, and a truncated email on the join and account-without-a-lab pages now shows the full address on hover.