アイヌ語追加 (#428) (#433)

Reviewed-on: #433
Co-authored-by: miteruzo <miteruzo@naver.com>

frontend/src/lib/helpPrefetch.test.tsx

@@ -43,7 +43,7 @@ describe ('Help prefetch integration', () => {
 	  <PrefetchLink to="/help/guide">Help</PrefetchLink>
 	  <Routes>
 	    <Route path="/" element={null}/>
-	    <Route path="/help/:identifier" element={<HelpDetailPage/>}/>
+	    <Route path="/ja/help/:identifier" element={<HelpDetailPage/>}/>
 	  </Routes>
 	</>)
     const loader = helpFixture.moduleLoads['../../help/guide/editions/ja/2026-10-02.10.mdx']
@@ -84,14 +84,14 @@ describe ('Help prefetch integration', () => {
 	  <PrefetchLink to={path}>diff</PrefetchLink>
 	  <Routes>
 	    <Route path="/" element={null}/>
-	    <Route path="/help/:identifier/diff" element={<HelpDiffPage/>}/>
+	    <Route path="/ja/help/:identifier/diff" element={<HelpDiffPage/>}/>
 	  </Routes>
 	</>)
     await Promise.all ([prefetchers.prefetchForURL (queryClient, path),
 	prefetchers.prefetchForURL (queryClient, path)])
     fireEvent.click (screen.getByRole ('link', { name: 'diff' }))
     expect (await screen.findByRole ('link', { name: '旧ホーム (2026-10-01)' }))
-	.toHaveAttribute ('href', '/help/guide?edition=2026-10-01')
+	.toHaveAttribute ('href', '/ja/help/guide?edition=2026-10-01')
     expect (screen.getByText ('+ # ホーム第十版')).toBeInTheDocument ()
     Object.entries (helpFixture.raw).forEach (([name, load]) => {
       const expected = /\/ja\/(2026-10-01|2026-10-02\.10)\.mdx$/.test (name) ? 1 : 0