feat: paginate starred questions pages

[btfcookies]

Resolves #552

Summary

• Add a shared renderPagination helper (client/scripts/utilities/pagination.js) that renders a Bootstrap pagination nav (first/prev/page numbers/next/last, windowed to avoid huge lists) and wires up click handling via a callback — mirrors the pagination UX already used on the DB search page.
• Rework the starred tossups and starred bonuses pages to render 20 items per page instead of the full list at once, using the new helper. Card rendering, star/unstar listeners, and pagination controls are re-rendered per page change; clicking a new page scrolls back to the top of the list.
• Add an empty-state message ("You have no starred tossups/bonuses.") when the list is empty.
• Existing behavior is preserved: "Clear Starred" and the TXT/CSV/JSON downloads still operate on the entire starred list, not just the visible page.

Testing

I was not able to test this locally since only users with accounts can star questions.
npx semistandard passes on all changed or added files
npm run webpack builds cleanly