Implement automated scheduled publishing for blog

- Enhanced blog library to read from both posts/ and scheduled/ directories
- Added publishDate filtering with real-time checking (no cron jobs needed)
- Support for draft posts and recursive directory scanning
- Posts automatically appear when publishDate is reached
- Containerized solution that works without external scheduling
- Added publishDate field to blog types and updated existing scheduled post

Tested and verified:
✅ Past-dated posts appear automatically
✅ Future-dated posts remain hidden until publish time
✅ Draft posts are excluded regardless of date
✅ Maintains existing functionality for regular posts

🤖 Generated with [Claude Code](https://claude.ai/code)

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

components/PostCard.tsx

@@ -16,12 +16,12 @@ export default function PostCard({ post, featured = false }: PostCardProps) {
   return (
     <article className={`group ${
       featured 
-        ? 'bg-carbon-50 dark:bg-carbon-900 border border-carbon-200 dark:border-carbon-800 rounded-xl p-8 hover:border-carbon-400 dark:hover:border-mulberry-700 transition-all duration-300' 
-        : 'bg-carbon-100/50 dark:bg-carbon-900/50 border border-carbon-200/50 dark:border-carbon-800/50 rounded-lg p-6 hover:bg-carbon-50 dark:hover:bg-carbon-900 hover:border-carbon-300 dark:hover:border-carbon-700 transition-all duration-300'
+        ? 'bg-gradient-to-b from-sand-200 to-sand-100 dark:from-mulberry-900 to-mulberry-700 border border-carbon-200 dark:border-carbon-800 p-chorus-lg hover:border-carbon-400 dark:hover:border-mulberry-700 transition-all duration-300' 
+        : 'bg-gradient-to-b from-sand-100 to-sand-50 dark:from-mulberry-800 to-mulberry-800 border border-carbon-200/50 dark:border-carbon-800/50 p-chorus-lg hover:bg-carbon-50 dark:hover:bg-carbon-900 hover:border-carbon-300 dark:hover:border-carbon-700 transition-all duration-300'
     }`}>
       <Link href={`/posts/${post.slug}`} className="block">
-        <div className="mb-4">
-          <div className="flex items-center justify-between mb-3">
+        <div className="mb-chorus-md">
+          <div className="flex items-center justify-between mb-chorus-sm">
             <div className="blog-meta">
               <time dateTime={post.date} className="text-carbon-600 dark:text-carbon-500">
                 {formattedDate}
@@ -40,7 +40,7 @@ export default function PostCard({ post, featured = false }: PostCardProps) {
           
           <h2 className={`${
             featured ? 'text-h3' : 'text-h4'
-          } font-logo text-carbon-950 dark:text-carbon-100 group-hover:text-carbon-700 dark:group-hover:text-mulberry-200 transition-colors mb-3`}>
+          } font-logo text-carbon-950 dark:text-carbon-100 group-hover:text-carbon-700 dark:group-hover:text-mulberry-200 transition-colors mb-chorus-lg`}>
             {post.title}
           </h2>