feat(frontend): improve security meta tags, performance (preload) and cleanup comments

Author: ftosoni

frontend/index.html

@@ -29,14 +29,15 @@
     <meta name="author" content="Francesco Tosoni">
     <meta http-equiv="X-Content-Type-Options" content="nosniff">
     <meta http-equiv="Referrer-Policy" content="strict-origin-when-cross-origin">
+    <link rel="preload" href="css/style.css" as="style">
 
     <!-- Social Media (Open Graph) -->
     <meta property="og:type" content="website">
     <meta property="og:url" content="https://code2codesearch.toolforge.org/">
     <meta property="og:title" content="MediaWiki Code2Code Search | Semantic Neural Retrieval">
     <meta property="og:description"
         content="Advanced AI-powered semantic search for MediaWiki source code. Search by meaning, not just keywords.">
-    <meta property="og:image" content="https://code2codesearch.toolforge.org/icon.png">
+    <meta property="og:image" content="https://code2codesearch.toolforge.org/assets/branding/logo-horizontal.svg">
 
     <!-- Icons & Canonical -->
     <link rel="canonical" href="https://code2codesearch.toolforge.org/">