ui(avbeat): shrink featured-story hero excerpt ~50%

FeaturedBentoFromDb.tsx:119 — hero excerpt size ramp halved:
  text-base md:text-lg  (16 / 18 px)
  → text-xs md:text-sm  (12 / 14 px)

Restores a clear size gap below the (already-shrunk) hero headline; the
excerpt was visually competing with the title at the same breakpoint.

src/components/FeaturedBentoFromDb.tsx

@@ -116,7 +116,7 @@ export default async function FeaturedBento() {
                   {hero.title}
                 </h3>
                 {hero.excerpt && (
-                  <p className="font-serif text-base md:text-lg text-[#cbd5e1] mt-3 max-w-2xl line-clamp-2">
+                  <p className="font-serif text-xs md:text-sm text-[#cbd5e1] mt-3 max-w-2xl line-clamp-2">
                     {cleanExcerpt(hero.excerpt)}
                   </p>
                 )}