No guidance on setting up and using webhooks with `shopify-app-node-template`

Issue summary

I am attempting to set up Webhooks in a shopify app generated by the shopify-app-node-template. There is no clear documentation I can find about how to do this, apart from the docs for shopify-api-js.

However, the template has already done a lot of this for us, but it is hidden amongst unreadable node-module packages. How am I supposed to register a Webhook after the OAuth callback without overriding the boiler plate that Shopify has included in this template?

What is the correct way to process them after this? Where is the /api/webhooks endpoint that the boiler plate code sets being used? I can't find it in the template.

This is straight forward in the docs for shopify-api-js, however this is utterly and extremely unclear what the pattern should be for using using Webhooks with this template without overriding the boiler plate code, and there are no docs I can find specifically to guide me.

Can anyone please help point me to the correct docs for how to set up and use Webhooks within this template?

Start with the shopify-app-node-template OAuth callback and the /api/webhooks endpoint, then compare their behavior with the linked shopify-api-js webhook documentation. Document how webhook registration fits into the generated template and how incoming webhooks are processed; done means a newcomer can follow the documented pattern without replacing the boilerplate.