OpenAI changed Navier-Stokes press release and Lean4 code on GH

As of Sept, 11th: https://openai.com/index/navier-stokes-solution/

Compare to https://web.archive.org/web/20260908235305/https://openai.com/index/navier-stokes-solution/

Also, see GitHub - git history: https://github.com/openai/NavierStokesAndEuler