Docs site URL returns 404 (Pages not deployed / mkdocs URL mismatch)

[adust09]

The documented docs URL currently returns 404:

• https://leanethereum.github.io/lean-spec/

Observed in this repository:

• mkdocs.yml points to lean-spec (site_url and repo_url), but the git remote is leanEthereum/leanSpec.
• The GitHub Pages project URL is typically https://.github.io//, so if the repo is leanSpec, the .../leanSpec/ side is likely the correct one.

Expected:

• The docs site is reachable from the documented URL
• mkdocs.yml URLs match the actual repository path
• A Pages deployment workflow exists (or docs explicitly state that public hosting is disabled)

If necessary, the following can be implemented:

1. Update site_url / repo_url in mkdocs.yml to leanSpec
2. Add Pages publishing workflow (actions/configure-pages + actions/deploy-pages)
3. Set GitHub Pages in GitHub Settings to GitHub Actions source