Update welcome post content and formatting; implement dynamic blog owner name in layout and post metadata; add author field to post structure and API routes.

src/app/api/posts/[slug]/route.ts

@@ -39,6 +39,7 @@ async function getPostBySlug(slug: string) {
     summary: data.summary,
     content: processedContent.toString(),
     createdAt: createdAt.toISOString(),
+    author: process.env.NEXT_PUBLIC_BLOG_OWNER + "'s" || 'Anonymous',
   };
 }