feat: PublicShell + TopNav + 홈 v6 (ai_music_creator 참조)

- 사이드바 대시보드는 /admin, /mypage 에서만 사용
- 공개 페이지는 상단 TopNav + 다크 footer(PublicShell)
- 홈 v6: Hero + Evidence + Before/After + Toolkit + 3-Step + Other Products

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

app/components/PublicShell.tsx

@@ -0,0 +1,51 @@
+import TopNav from './TopNav';
+import Link from 'next/link';
+
+export default function PublicShell({ children }: { children: React.ReactNode }) {
+  return (
+    <>
+      <TopNav />
+      <main
+        className="min-h-screen pt-20"
+        style={{
+          background: 'var(--kx-surface)',
+          color: 'var(--kx-on-surface)',
+        }}
+      >
+        {children}
+        <footer
+          className="mt-20 px-6 lg:px-12 py-10 text-xs"
+          style={{
+            background: 'var(--kx-surface-low)',
+            color: 'var(--kx-on-variant)',
+            borderTop: '1px solid rgba(255,255,255,0.05)',
+          }}
+        >
+          <div className="max-w-7xl mx-auto">
+            <div className="flex flex-col md:flex-row justify-between gap-6 mb-5">
+              <div>
+                <p className="kx-display font-extrabold text-lg mb-2" style={{ color: 'var(--kx-on-surface)' }}>쟁승메이드</p>
+                <p className="leading-relaxed max-w-md">
+                  AI 음악·블로그 자동화·사주 분석까지. 현직 엔지니어가 직접 설계·운영하는 AI 크리에이티브 스토어.
+                </p>
+              </div>
+              <div className="flex flex-wrap gap-x-6 gap-y-2">
+                <Link href="/legal/terms" className="hover:text-white transition">이용약관</Link>
+                <Link href="/legal/privacy" className="hover:text-white transition">개인정보처리방침</Link>
+                <Link href="/legal/refund" className="hover:text-white transition">환불 정책</Link>
+              </div>
+            </div>
+            <div className="pt-5 border-t flex flex-wrap gap-x-4 gap-y-1 leading-relaxed" style={{ borderColor: 'rgba(255,255,255,0.05)' }}>
+              <span>대표자: 박재오</span>
+              <span>사업자등록번호: 267-53-00822</span>
+              <span>주소: 서울시 동작구 여의대방로22아길 22, 1동 109호</span>
+              <span>전화: 010-3907-1392</span>
+              <span>이메일: bgg8988@gmail.com</span>
+            </div>
+            <p className="mt-3">© 2026 쟁승메이드. All rights reserved.</p>
+          </div>
+        </footer>
+      </main>
+    </>
+  );
+}