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

index.html

@@ -12,6 +12,12 @@
     <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent" />
     <meta name="format-detection" content="telephone=no" />
     <title>Loading...</title>
+    <link rel="preconnect" href="https://fonts.googleapis.com" />
+    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
+    <link
+      href="https://fonts.googleapis.com/css2?family=Manrope:wght@400;500;600;700;800&display=swap"
+      rel="stylesheet"
+    />
     <script src="https://telegram.org/js/telegram-web-app.js"></script>
     <style>
       body {