refactor: enhance PostElement structure and update blog schema

- Wrapped the post link in an <article> tag for improved semantic structure.
- Updated blogSchema to include posts for better structured data representation.
- Adjusted the blog index to utilize the new posts parameter for enhanced SEO.

src/pages/blog/index.astro

@@ -30,6 +30,7 @@ const lang = "en";
 const schema = blogSchema({
 	siteUrl: new URL("/", Astro.site).toString(),
 	title,
+	posts,
 });
 ---