add docs site

We need a docs site that meets the following requirements:
- All files are in commonmark markdown (frontmatter ok) in a folder in the root repo on the default branch such as /docs/public/.
- A change in the main branch automatically deploys to the public site
- Published at auth.activescott.com
- Github pages acceptable, not required.
- Docs should make the raw markdown available as "View as Markdown" link that allows LLM-based agents reading docs to read only markdown. The markdown link should be a consistent pattern like .md or something (where the normal page just has no .md postfix).
- There should be a link to "edit this page" that takes to github UI edtior that allows anyone to make an edit and submit a PR easily (there is some link to edit any file in github UI).
- Prolly use https://docusaurus.io

Includes docs for following:
- A home page that is basically the info in the readme - about the package, and how to use it. Should be kept in sync with the repo readme (not necessarily mechanically, fine to use comments int he readme and the docs root page to remind humans and agents to keep them in sync).
- SMS via Twilio Messaging verses SMS via Twilio Verify: How to choose:
- TLDR SMS via Twilio Verify (quick setup, cheaper at low volume), SMS via Twilio Messaging (slow setup, cheaper at high volume)
- How to setup Twilio SMS delivery and exactly what to complete in the US A2P 10DLC form application. Also how to troubleshoot twilio (view the logs)
- Using cloudflare email service (over SMTP): https://developers.cloudflare.com/email-service/api/send-emails/smtp/ including if any DNS records need setup (SPF, DKIM, DMARC) - although I _think_ cloudflare does this.
- Using a gmail account to deliver email (and the consequences).
- what else??