feat: add favicon to the documentation site

Author: Bharath-code

docs/favicon.png

@@ -13,6 +13,7 @@
     <meta name="author" content="Bharath Kumar">
     <meta name="theme-color" content="#8B5CF6">
     <meta name="robots" content="index, follow">
+    <link rel="icon" type="image/png" href="favicon.png">
     <meta name="google-site-verification" content="TpPfXeUVDiIUimzkBojIiZ6zm1iBBE2gxDkOt8G4Hjo" />
     <!-- Schema.org for Google/AI Search -->
     <script type="application/ld+json">