fix(web): all accent text and icons use accent-fg (#5318)

The raw accent fails AA as text on every dark surface, not only on its
own tint: 3.04:1 on the page, 2.70 on iron, 2.21 on slate, against 4.5.
accent-fg (the house formula, 45% toward parchment) measures 5.62 at
worst across both modes. The operator chose the readable colour over the
signature teal for text, on 2026-10-08.

- 36 sites swap. They are 35 Tailwind uses: links, "Now playing", the
  ingest progress line, active shuffle/repeat, the liked heart, the app
  download icon and its hover. The last is the alphabet rail's pending
  spinner in CSS. Icons follow the text: as graphics they need only
  3:1, and the raw accent misses even that on iron.
- check-tint-contrast adds accent to TEXT_NEVER_RAW, so a new raw
  text-accent or color: var(--fs-accent) fails the web lane. Run against
  the files before the swap, it finds all 36. Borders, rings and fills
  keep the raw accent.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/routes/artists/[id]/+page.svelte

@@ -73,7 +73,7 @@
   {#if notFound}
     <div role="alert" class="rounded border border-border bg-surface p-4">
       <p>Artist not found.</p>
-      <a href="/" class="mt-2 inline-block text-sm text-accent">Back to Library</a>
+      <a href="/" class="mt-2 inline-block text-sm text-accent-fg">Back to Library</a>
     </div>
   {:else if query.isError}
     <ApiErrorBanner error={query.error} onRetry={query.refetch} />