style: center header content with mx-auto

Added mx-auto to navbar container to center the header content.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

components/layout/Navbar.tsx

@@ -51,7 +51,7 @@ export function Navbar() {
 
   return (
     <nav className="sticky top-0 z-50 w-full border-b bg-background/95 backdrop-blur supports-[backdrop-filter]:bg-background/60">
-      <div className="container flex h-16 items-center px-4 md:px-6">
+      <div className="container mx-auto flex h-16 items-center px-4 md:px-6">
         {/* Logo */}
         <Link href="/" className="flex items-center gap-2 mr-4 md:mr-8">
           <Activity className="h-6 w-6 text-primary" />