perf: shrink Material Symbols icon font and favicon

The icon font URL requested the full variable font across every axis range
(opsz/wght/FILL/GRAD), making Google serve a ~3.8MB woff2 - the single largest
resource on every page and the long pole on the load event. Only wght 200-400
and FILL 0/1 are actually used, so pin opsz=24/GRAD=0 and narrow the ranges:
Google now serves a ~1.1MB instance (-72%). Also downscale favicon.png from
809x809/104KB to 64x64/2.7KB.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ashtonanderson

public/favicon.png

@@ -82,9 +82,19 @@ function MaiaPlatform({ Component, pageProps }: AppProps) {
         >
           <Head>
             <link rel="icon" type="image/png" href="/favicon.png" />
+            <link
+              rel="preconnect"
+              href="https://fonts.gstatic.com"
+              crossOrigin="anonymous"
+            />
+            {/*
+              Pin the optical-size and grade axes (only wght 200-400 and FILL
+              0/1 are actually used) so Google serves a ~1.1MB instance instead
+              of the full ~3.8MB variable font.
+            */}
             <link
               rel="stylesheet"
-              href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined:opsz,wght,FILL,GRAD@20..48,100..700,0..1,-50..200&display=block"
+              href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined:opsz,wght,FILL,GRAD@24,200..400,0..1,0&display=block"
             />
 
             <meta name="apple-mobile-web-app-capable" content="yes" />