Brings the merged Link component work (PR #3868) plus panelstack and
carousel fixes onto the new Button system.
Conflict resolutions:
- about/{index,history,impact}.page.tsx: keep both branches' imports;
/about CTAs use the new Button; Link component retained for the
inline validators links and FAQ markup.
- StandardCard: link color moves to $black/$lilac-500. Required, not
cosmetic: the branch's $bds-btn-neutral-black no longer exists after
the Button token system was replaced by $bds-btn-palette.
- Compiled CSS regenerated via npm run build-css rather than resolved
by hand.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
