AWS Amplify preset doesn't support mixed render modes

Describe the feature

The current preset does not support mixed render modes, e.g. Nuxt can deliver a SSR App with some prerendered pages. Amplify has issues to detect if a requested route is SSR or SSG, by default its calling SSR. If the route is SSG, this will result in a 500 error, because there is no "fallthrough". The preset itself support SSG, but only if the complete app i SSG, not mixed.

I think there are multiple possible solutions:

1. Fallthrough: Serve statically all assets, if asset does not exists in bucket, the Server is requested
2. Cloudfront Function / Lambda@Edge: A function with least possible overhead acts in front of the app, reads route config and pass request to right location
3. SSR with long revalidation and warmup: Despite prerendering is configured, actually all routes are rendered with SWR and after build a warmup request triggers cache to have near SSG performance

Also look inside other presets for inspiration (Netlify / Vercel).

Just some ideation, not tested

export default defineNitroPreset({
  name: 'amplify-static-fallback',
  extends: 'aws-amplify',
  hooks: {
    // After Nitro has compiled server + static assets
    'nitro:compiled': async (nitro) => {
      const outDir = nitro.options.output.dir
      const manifestDir = join(outDir, '.amplify-hosting')
      const staticDir = nitro.options.output.publicDir

      // Ensure the folder exists
      await fs.mkdir(manifestDir, { recursive: true })

      // Deploy manifest: single static-first + SSR fallback
      const deployManifest = {
        version: 1,
        appRoot: outDir,
        staticAssets: {
          root: staticDir
        },
        routes: [
          {
            path: '/*',
            target: { kind: 'Static' },
            fallback: { kind: 'Compute', src: 'default' }
          }
        ]
      }

      const manifestPath = join(manifestDir, 'deploy-manifest.json')
      await fs.writeFile(manifestPath, JSON.stringify(deployManifest, null, 2))

      console.log('[Amplify Preset] Written static-first + fallback deploy-manifest.json')
    }
  }
})

Additional information

• Would you be willing to help implement this feature?

Start with the AWS Amplify preset and its nitro:compiled entry point, then compare the Netlify and Vercel presets for handling mixed SSR and SSG routes. Define and validate one approach that serves prerendered routes without a 500 while retaining SSR fallback; the issue does not name a specific test or file.