feat: add proper favicon and logo for landing page and docs site

Generated favicon files (ico, 16x16, 32x32, 180x180, 192x192, 512x512)
from the Hermes Agent logo. Replaces the inline SVG caduceus emoji with
real favicon files so Google's favicon service can pick up the logo.

Landing page: updated <link> tags to reference favicon.ico, favicon PNGs,
and apple-touch-icon.
Docusaurus: updated config to use favicon.ico and logo.png instead of
favicon.svg.

website/docusaurus.config.ts

@@ -5,7 +5,7 @@ import type * as Preset from '@docusaurus/preset-classic';
 const config: Config = {
   title: 'Hermes Agent',
   tagline: 'The self-improving AI agent',
-  favicon: 'img/favicon.svg',
+  favicon: 'img/favicon.ico',
 
   url: 'https://hermes-agent.nousresearch.com',
   baseUrl: '/docs/',
@@ -53,7 +53,7 @@ const config: Config = {
       title: 'Hermes Agent',
       logo: {
         alt: 'Hermes Agent',
-        src: 'img/favicon.svg',
+        src: 'img/logo.png',
       },
       items: [
         {