How can an Addon extend host app Router automatically?

Hi all. New to developing addons here.

I’m developing some project specific addons. I need the addons to add routes to the host app when installed. I understand that the addon’s /app tree is merged with the host app when installed. However, I notice the addon’s routes are not registered in the host app router. How can I accomplish this?

Ideally, I’d like to be able to write an extension the router as suggested in the thread linked below. However, in that example, the host app needs to import the mixin to the router. For my use case, I need the routes to be registered automatically without manual modifications to the host app.

Any guidance?