<x-sort-header> renders data-md-sort-header (data-md-active on the
sorted column) with its button and arrow as data-md-* attributes; the
button keeps md-focus-ring and md-touch-target, the arrow takes size 16,
and the hover and hint-arrow states move into components/sort-header.css
(plan step 36). A browser test presses the button at the edge of its
48px target.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9
