feat(shell): DashboardShell STANDALONE_PATHS에 /gyeol 추가

CONTOUR 설문 페이지는 자체 시각 정체성 — TopNav/푸터/카카오 모두 숨김.
풀스크린 설문 UI 집중도 보장.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/components/DashboardShell.tsx

@@ -3,7 +3,7 @@
 import { usePathname } from 'next/navigation';
 import PublicShell from './PublicShell';
 
-const STANDALONE_PATHS = ['/login', '/signup', '/admin'];
+const STANDALONE_PATHS = ['/login', '/signup', '/admin', '/gyeol'];
 
 export default function DashboardShell({ children }: { children: React.ReactNode }) {
   const pathname = usePathname();