Facts docs use a dedicated custom subdomain

Facts will publish its documentation site at https://facts.martinez.io/ from this repository, rather than under the existing martinez.io personal site or the default ncode.github.io/facts repository Pages URL. The site should stay independently deployable from the Facts repo, with GitHub Pages serving the generated site and a CNAME for facts.martinez.io.

Considered Options

• Use facts.martinez.io - chosen: it gives Facts a stable public URL while keeping the project docs independent from the existing personal site.
• Use martinez.io/facts - rejected: it would couple Facts documentation deployment and routing to the personal website.
• Use ncode.github.io/facts - rejected: it works as a fallback, but the custom domain is cleaner for public documentation.