feat: 내부 테스트 페이지 route 추가

src/app/[lang]/internal/page.test.tsx

@@ -0,0 +1,38 @@
+import { render, within } from '@testing-library/react';
+import { describe, expect, it } from 'vitest';
+
+import InternalPage, { generateMetadata, generateStaticParams } from './page';
+
+describe('/[lang]/internal page', () => {
+  it('generates locale params for internal test pages', () => {
+    expect(generateStaticParams()).toEqual([{ lang: 'en' }, { lang: 'ja' }, { lang: 'ko' }]);
+  });
+
+  it('renders the Korean internal page title and description only', async () => {
+    const container = document.createElement('div');
+    const result = render(await InternalPage({ params: Promise.resolve({ lang: 'ko' }) }), {
+      baseElement: container,
+      container,
+    });
+
+    expect(within(result.container).getByRole('heading', { level: 1, name: '내부 페이지' })).toBeTruthy();
+    expect(
+      within(result.container).getByText('검토와 구현 참고를 위해 유지 중인 내부 컴포넌트 및 페이지 예시 목록입니다.'),
+    ).toBeTruthy();
+    expect(within(result.container).queryByRole('list')).not.toBeInTheDocument();
+  });
+
+  it('uses the same copy for route metadata', async () => {
+    await expect(generateMetadata({ params: Promise.resolve({ lang: 'ko' }) })).resolves.toMatchObject({
+      description: '검토와 구현 참고를 위해 유지 중인 내부 컴포넌트 및 페이지 예시 목록입니다.',
+      title: '내부 페이지',
+    });
+  });
+
+  it('falls back to English metadata when static generation omits params', async () => {
+    await expect(generateMetadata({})).resolves.toMatchObject({
+      description: 'A list of internal component and page examples maintained for review and implementation reference.',
+      title: 'Internal Pages',
+    });
+  });
+});

src/app/[lang]/internal/page.tsx

@@ -0,0 +1,94 @@
+import type { Metadata } from 'next';
+
+type InternalPageParams = {
+  lang: string;
+};
+
+type InternalPageProps = {
+  params?: Promise<InternalPageParams | undefined>;
+};
+
+type InternalPageCopy = {
+  description: string;
+  title: string;
+};
+
+const internalPageCopy: Record<string, InternalPageCopy> = {
+  en: {
+    description: 'A list of internal component and page examples maintained for review and implementation reference.',
+    title: 'Internal Pages',
+  },
+  ja: {
+    description: 'レビューと実装参考のために維持している内部コンポーネントおよびページ例の一覧です。',
+    title: '内部ページ',
+  },
+  ko: {
+    description: '검토와 구현 참고를 위해 유지 중인 내부 컴포넌트 및 페이지 예시 목록입니다.',
+    title: '내부 페이지',
+  },
+};
+
+const locales = Object.keys(internalPageCopy);
+
+function getInternalPageCopy(lang: string) {
+  return internalPageCopy[lang] ?? internalPageCopy.en;
+}
+
+async function getInternalPageLang(params: InternalPageProps['params']) {
+  const resolvedParams = await params;
+
+  return resolvedParams?.lang ?? 'en';
+}
+
+export function generateStaticParams() {
+  return locales.map(lang => ({ lang }));
+}
+
+export async function generateMetadata({ params }: InternalPageProps): Promise<Metadata> {
+  const lang = await getInternalPageLang(params);
+  const copy = getInternalPageCopy(lang);
+
+  return {
+    description: copy.description,
+    title: copy.title,
+  };
+}
+
+export default async function InternalPage({ params }: InternalPageProps) {
+  const lang = await getInternalPageLang(params);
+  const copy = getInternalPageCopy(lang);
+
+  return (
+    <section
+      style={{
+        margin: '0 auto',
+        maxWidth: '768px',
+        padding: '64px 24px',
+      }}
+    >
+      <h1
+        style={{
+          color: '#111318',
+          fontSize: '36px',
+          fontWeight: 700,
+          letterSpacing: '0',
+          lineHeight: 1.2,
+          margin: '0 0 16px',
+        }}
+      >
+        {copy.title}
+      </h1>
+      <p
+        style={{
+          color: '#454a53',
+          fontSize: '17px',
+          letterSpacing: '0',
+          lineHeight: 1.7,
+          margin: 0,
+        }}
+      >
+        {copy.description}
+      </p>
+    </section>
+  );
+}