feat: TopNav 뮤직 중심 재편 (Home/Showcase/Pricing/API)

블로그 팩·AI 사주 제거 — 홈 '다른 도구들' 카드로 유지
음악 메인 상품 포커스 강화

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/components/TopNav.tsx

@@ -6,10 +6,9 @@ import { useState, useEffect } from 'react';
 
 const LINKS = [
   { href: '/', label: 'Home' },
-  { href: '/services/music', label: 'AI 음악' },
+  { href: '/services/music#samples', label: 'Showcase' },
-  { href: '/services/blog', label: '블로그 팩' },
+  { href: '/services/music#pricing', label: 'Pricing' },
-  { href: '/saju', label: 'AI 사주' },
+  { href: '/services/music', label: 'API' },
-  { href: '/legal/refund', label: '환불정책' },
 ];
 
 export default function TopNav() {