Remove or simplify outdated "Deploy" instructions from repo README

[alyssadai]

Our cd.yaml workflow auto-deploys on push to main, so we no longer need to call mkdocs gh-deploy manually as currently described in the README.

[NobleCoder69]

Hi @alyssadai , I’d like to work on this issue. Should the outdated manual deploy instructions be removed entirely, or replaced with a note explaining that deployment is now automatic via "cd.yaml"?

[github-actions]

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