perf: improve LCP — move font loading to HTML, defer logo preload

- Move Google Fonts from CSS @import (render-blocking) to <link> in
  index.html with preconnect for earlier discovery
- Remove @import from globals.css — browser no longer waits for CSS
  parse -> @import fetch -> font CSS parse before first paint
- Defer initLogoPreload() to requestIdleCallback so logo fetch
  doesn't compete with critical resources during page load

src/main.tsx

@@ -92,8 +92,12 @@ if (!alreadyInitialized) {
   }
 }
 
-// Preload logo from cache immediately on page load
-initLogoPreload();
+// Preload logo from cache — defer to idle time so it doesn't compete with LCP
+if ('requestIdleCallback' in window) {
+  requestIdleCallback(() => initLogoPreload());
+} else {
+  setTimeout(initLogoPreload, 100);
+}
 
 const queryClient = new QueryClient({
   defaultOptions: {