For now, I am using Webmention.io to handle the heavy lifting of providing the Webmention end-point, the same way the above-referenced article describes.
With only minor modifications to the Node.js script from the article, I can pull down all
mentions for my domain from Webmention.io and save them out as Hugo data files in my
data/webmentions folder. For now, this is a manual process that I trigger from my
laptop. Eventually, I should be able to set up a cron job on a server to periodically
fetch new mentions, add them to my Gitea repository, and then push them out to the
Gitlab mirror so Netlify will automatically rebuild the site.
Further down the road, I plan to implement Micropub for the site. Once I have end-points for Micropub, it only makes sense to also self-host the end-point(s) for webmentions. At that point, either I will implement my own webmention end-point, or look into deploying the open source Webmention.io code on my own server.
If all goes well, once I get this post served up, I will be able to add in a webmention from Webmention Rocks! that will show up below.