Hi oldman
It could be that I’m intruding on the conversation with something that isn’t interesting.
But, I don’t use npm and I can run all the example pages from the Three.js website at home, through a simple local web server (a very simple PHP server).
I download the complete Three.js zip from the page itself:
https://threejs.org/, in the menu on the left…
Code
github
download…
and clicking download comes the entire set of Three.js documents and codes.
When running my local web server (127.0.0.1/) and accessing the three.js-master directory I can access the editor subdirectory and run its index.html.
I can access the examples subdirectory and run the infinite html pages contained therein.
So I would like to know what Your home web server is, and maybe I can help You.
Through the editor, I think it is only possible to import objects and set up a scene, but we cannot import an HTML page into the scene.
I hope I don’t confuse You, I just can’t go without making a comment. 
Respectfully,
José Roberto Lazzareschi
PS: I wrote an article a while ago and I was even criticized for using old methods to work with Three.js… Install and run Three.js in Windows in less than one hour … but so far they work very well.