feat!: typescript rewrite

[AlexStormwood]

WIP branch, but just noting this here to show that this is the thing currently being worked on in this package. Should also help address other open issues, like confirming if other document types work and if the document hooks work.

[github-actions]

Thankyou for the pull request!

As a reminder, here's the workflow we're aiming to use in this repository:

1. Make your work in a branch that is not main or deploy.
2. When working in your branch, make as many commits as you like in whatever commit syntax you like.
3. When your work in that branch is ready to merge back into main, make a pull request. <-- You are here
4. Make sure your pull request has a title that follows conventional commit syntax. Learn more about that here.
5. If appropriate, tag someone in to your PR and ask them to review your work. Learn more about pull request reviews here.
   a. If you were requested to do a review of a pull request, you can learn more about performing a review here.
6. Once the PR title has been approved and the PR has been reviewed (and approved!), you can carry out a "Squash and Merge" merge.

"Squash and merge" means all random commits within your branch will not be shown as separate commits in main. Rather, we'll have one single big commit with a message that matches this PR title. That's why our PR must follow certain rules, while your branch can be totally customised to however you want to work.

Good luck on your latest PR! 😄