Integrate SPA sveltekit no SSR with backend frameworks

[webbby]

I can't find a resource which explains how SPA, no-SSR sveltekit build should be integrated with backend frameworks and their templating solutions!

private
  sveltekit-project

public
  svelte-build   ---> build target dir where the build files are accessible from a client

backend-templates
   template      -----> import the SPA build from ../public/svelte-build as a resource into the template and yet
                               - be able to use sveltkit routing
                               - be able to client-side debug the SPA  during dev-builds

If one is to go out and beyond of the trivial sveltekit project structure there's no explanation whatsoever.
Anyone familiar with integration with backend templates?