`npm run dev` fails showing TypeRoof-player in docs iframe

[graphicore]

I wrote in #43 (comment)

Before considering to merge this, I think I want to change the way npm run dev works, more specifically the interplay between vite and eleventy. I hope https://www.npmjs.com/package/vite-plugin-eleventy can solve it. The issue: when running npm run dev go to http://localhost:3001/TypeRoof/docs/ there the TypeRoof player iframe dosesn't play the video, but shows a message TypeRoof-legacy / Video Proof has moved! The published docs show the correct behavior: https://fontbureau.github.io/TypeRoof/docs/
I believe that vite-plugin-eleventy should solve the issue and make the overall setup simpler, i.e. no need for the proxy configuration in vite.config.js

However, vite-plugin-eleventy is outdated and hard coded to load its own eleventy at version 1. I would rather prefer it uses the general eleventy version, which is currently at 3+something. Also changing it to use eleventy 3+something made it fail. I'm not sure if that approach would be good at all, the approach would have to be updated to test it.

Maybe, it's easier to fix the proxy in vite (I believe that's causing the issue), it's overall not too bad currently, at least the steps of build app then build doc are well recognizable. The page that is loaded instead of the player is the index.html redirection page.

NOTE: npm run build:serve creates a realistic result of the full experience, it does not live update however.