feat: add RocketIcon to Header component and update metadata with application icon

src/components/layout/Header.tsx

@@ -5,7 +5,7 @@ import { usePathname } from 'next/navigation';
 import { useSession, signOut } from 'next-auth/react';
 import { useTheme } from '@/contexts/ThemeContext';
 import { useState } from 'react';
-import { Avatar } from '@/components/ui';
+import { Avatar, RocketIcon } from '@/components/ui';
 
 export function Header() {
   const { theme, toggleTheme } = useTheme();
@@ -20,7 +20,7 @@ export function Header() {
     <header className="sticky top-0 z-50 border-b border-border bg-card/80 backdrop-blur-sm">
       <div className="mx-auto flex h-16 max-w-7xl items-center justify-between px-4">
         <Link href="/" className="flex items-center gap-2">
-          <span className="text-2xl">🚀</span>
+          <RocketIcon className="h-7 w-7 shrink-0 text-primary" />
           <span className="text-xl font-bold text-foreground">Workshop Manager</span>
         </Link>