On viewports below 640px the pagination row at Dashboard > Usage >
Details rendered the rows-per-page select plus the full numbered page
list plus the prev/next chevrons in one unwrapped flex row with no
horizontal padding. On a 390px phone the Rows: label was clipped on
the left and the next chevron was clipped on the right.
Add px-2 to the outer container so the pagination card has horizontal
breathing room. Switch the inner controls group to flex-wrap with
gap-2 on mobile (and gap-4 from sm: up) so the rows-per-page select
can wrap below the chevrons. Hide the numbered page buttons, the
1 / last anchors, and the ... ellipses below sm: -- only the prev,
current page indicator, and next chevrons render on mobile, which
keeps every control reachable while fitting inside the card.
Desktop layout (>= 640px) is unchanged.
Refs decolua/9router#1146
