fix invalid <a> nesting in PostList

Apply the same PostList structural fix as hype404 / viralmvp: drop
the card-wide <a> that broke the layout via HTML5 nested-link
auto-recovery. Layout CSS unchanged; this commit only updates
PostList.astro.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/PostList.astro

@@ -26,7 +26,6 @@ const fmt = (d) => new Date(d).toLocaleDateString('en-US',
 
 {enriched.length > 0 && !tag && hero && (
   <article class="post-hero" data-reveal>
-    <a class="post-hero-link" href={`/${hero.slug}/`}>
     {hero.cover && (
       <div class="post-hero-img">
         <img src={hero.cover} alt="" loading="eager" />
@@ -34,7 +33,9 @@ const fmt = (d) => new Date(d).toLocaleDateString('en-US',
     )}
     <div class="post-hero-body">
       <div class="post-hero-flag">Top story</div>
-        <h2 class="post-hero-title">{hero.title}</h2>
+      <h2 class="post-hero-title">
+        <a class="card-link" href={`/${hero.slug}/`}>{hero.title}</a>
+      </h2>
       <p class="post-hero-excerpt">{hero.rawExcerpt}</p>
       <div class="post-hero-meta">
         <span>{fmt(hero.date)}</span>
@@ -43,20 +44,20 @@ const fmt = (d) => new Date(d).toLocaleDateString('en-US',
         ))}
       </div>
     </div>
-    </a>
   </article>
 )}
 
 {(tag ? enriched : rest).map((post, i) => (
   <article class="post-row" data-reveal style={`animation-delay:${Math.min(i * 50, 500)}ms`}>
-    <a class="post-row-link" href={`/${post.slug}/`}>
     {post.cover && (
       <div class="post-row-img">
         <img src={post.cover} alt="" loading="lazy" />
       </div>
     )}
     <div class="post-row-body">
-        <h3 class="post-row-title">{post.title}</h3>
+      <h3 class="post-row-title">
+        <a class="card-link" href={`/${post.slug}/`}>{post.title}</a>
+      </h3>
       <p class="post-row-excerpt">{post.rawExcerpt}</p>
       <div class="post-row-meta">
         <time>{fmt(post.date)}</time>
@@ -65,7 +66,6 @@ const fmt = (d) => new Date(d).toLocaleDateString('en-US',
         ))}
       </div>
     </div>
-    </a>
   </article>
 ))}