fix: add middleware and api routes usage for nuxt (#947)

docs/quick-starts/framework/nuxt/README.mdx

@@ -38,6 +38,21 @@ import ApiResources from './api-resources/_index.mdx';
 
 <ApiResources />
 
+## Use in middleware or API routes \{#use-in-middleware-or-api-routes}
+
+The composable `useLogtoClient()` and `useLogtoUser()` are not available in middleware or API routes. You can use the `logtoEventHandler()` function to get the Logto client and other context:
+
+```ts title="api/auth/get-access-token.ts"
+import { logtoEventHandler } from '@logto/nuxt';
+
+export default defineEventHandler(async (event) => {
+  const config = useRuntimeConfig(event);
+  await logtoEventHandler(event, config);
+  const accessToken = await event.context.logtoClient.getAccessToken();
+  return { accessToken };
+});
+```
+
 ## Further readings \{#further-readings}
 
 <FurtherReadings />