feat: enhance SEO with sitemap and robots.txt, add Open Graph and Twitter meta tags

src/_includes/layout.njk

@@ -5,6 +5,36 @@
     <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
     <title>{{ title }}</title>
     <meta name="description" content="{{ description }}">
+    <!-- Open Graph Meta Tags -->
+    <meta property="og:title" content="{{ title }}">
+    <meta property="og:description" content="{{ description }}">
+    <meta property="og:type" content="article">
+    <meta property="og:url" content="{{ site.url }}{{ page.url }}">
+    <meta property="og:image" content="{{ image }}">
+    <!-- Twitter Card Meta Tags -->
+    <meta name="twitter:card" content="summary_large_image">
+    <meta name="twitter:title" content="{{ title }}">
+    <meta name="twitter:description" content="{{ description }}">
+    <meta name="twitter:image" content="{{ image }}">
+    <!-- Structured Data (JSON-LD) -->
+    <script type="application/ld+json">
+    {
+        "@context": "https://schema.org",
+        "@type": "BlogPosting",
+        "headline": "{{ title }}",
+        "description": "{{ description }}",
+        "image": "{{ image }}",
+        "author": {
+            "@type": "Person",
+            "name": "{{ site.author.name }}"
+        },
+        "datePublished": "{{ date }}",
+        "mainEntityOfPage": {
+            "@type": "WebPage",
+            "@id": "{{ site.url }}{{ page.url }}"
+            }
+    }
+    </script>
     <script src="https://cdn.tailwindcss.com"></script>
     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css">
     <link rel="preconnect" href="https://fonts.googleapis.com">