feat(abstracts): formal abstract for fully homomorphic encryption from GSW (#486) - #1077

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/

Not declared at the PR head: `.Randomized`, `pk_d`. Advisory only; see the job summary.