Add Next.js project with internationalization support

- Set up Next.js 15 with TypeScript, ESLint, and Tailwind CSS
- Add i18n support for Korean, English, and Japanese
- Implement language switcher and navigation components
- Update .gitignore to exclude node_modules, IDE files, and build artifacts

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

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

next-env.d.ts

@@ -0,0 +1,6 @@
+/// <reference types="next" />
+/// <reference types="next/image-types/global" />
+/// <reference path="./.next/types/routes.d.ts" />
+
+// NOTE: This file should not be edited
+// see https://nextjs.org/docs/app/api-reference/config/typescript for more information.