Fix oversized watch history thumbnails on mobile

- Replaced `w-full` with `w-56 max-w-full` in `.watch-history-card__thumbnail` class.
- This ensures thumbnails are constrained to ~224px (14rem) on all viewports, fixing the "bleeding" issue on mobile while maintaining the desktop layout.
- The `max-w-full` ensures safety on very narrow screens.

css/tailwind.source.css

@@ -3243,7 +3243,7 @@
   }
 
   .watch-history-card__thumbnail {
-    @apply block flex-none text-text no-underline w-full sm:w-56;
+    @apply block flex-none text-text no-underline w-56 max-w-full;
   }
 
   .watch-history-card__thumbnailInner {