fix(admin): add catch-all route redirect to handle /en and unknown paths

apps/admin/src/App.tsx

@@ -154,6 +154,9 @@ function App() {
             <Route path="/backup/media" element={<BackupMediaPage />} />
           </Route>
         </Route>
+
+        {/* Catch-all fallback */}
+        <Route path="*" element={<Navigate to="/" replace />} />
       </Routes>
     </BrowserRouter>
   )