fix: match banner and popular list width to the latest cards

Size the banner and the popular rank list to the same responsive widths as
the latest section's message bubbles (680/900/1120), so the banner, latest
cards and popular cards line up at one consistent content width on desktop.

Desktop-scoped; mobile stays full-width.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/FigmaBanner.tsx

@@ -301,7 +301,7 @@ export function FigmaBanner() {
   ) : null;
 
   return (
-    <div className="relative md:mx-auto md:max-w-[680px] lg:max-w-[800px]">
+    <div className="relative md:mx-auto md:max-w-[680px] lg:max-w-[900px] xl:max-w-[1120px]">
       <div
         ref={scrollerRef}
         onPointerDown={handlePointerDown}