feat(Classes/Sparse): Kadin's theorem, PH ⊆ P^{NP[O(log n)]} under a sparse Turing-complete set for NP (#2062 M3) - #2077

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/