Codex audit fixes: home3 read-time, /art OG/canonical, Bloom medallion centering

- home3 dropped source_read_minutes when mapping the brief item, so the badge
  only ever showed "1 min brief" — include it so "· ~N min full story" appears.
- /art is public but shipped the homepage title/canonical/OG (SSR-off shell, so
  svelte:head can't fix scrapers) — add /art to patch-static-heads.mjs.
- Bloom: center the circular motif in the tile's visual field (~43%) instead of
  the top illustration zone, so it reads as a medallion (per Jay + Codex).
- Polish: prefers-reduced-motion disables the tile hover-lift; fix stale
  patch-play-head.mjs comment reference.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/scripts/patch-static-heads.mjs

@@ -32,6 +32,12 @@ const PAGES = [
     title: 'On This Day · upbeatBytes',
     desc: 'One genuinely good thing that happened on this day in history.',
   },
+  {
+    file: 'art.html', path: '/art',
+    title: 'Daily Art · upbeatBytes',
+    desc: "A masterwork a day from the world's open museum collections — beautifully framed, " +
+          'with a short note on what you’re looking at.',
+  },
 ];
 
 function subsFor(url, title, desc) {