I maintain an ASP.NET MVC web application that uses the conventional MVC architecture except for any route that starts with /admin, which is handled by an older WebForms architecture. The MVC and WebForms code coexist in the same .NET 4.8 Framework project, and the user of the site can't even tell there's any difference, because the styling is the same and we use url prettifying tricks so that you can request /admin/something rather than /admin/Something.aspx.
This all works fine, except that WebForms is really showing its age and now we want to port the admin stuff to Vue. But I can't figure out how to deploy Vue such that it has the same coexistence with MVC.
I know that I could continue to use Razor pages and add Vue with a script tag, progressive enhancement style, but I think that makes it impossible to use single file components, which is one of the Vue features that seems important.
It seems like the most functional way to use Vue is to create a proper Vue site, with build step tooling, but how can I do this within an existing MVC project and just delegate one route to the new code, and port other routes over as needed?