implement core replay buffer logic - #792

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@11d5960a326750d5838078e36cf38b85af677262, mamba-org/setup-micromamba@4b9113af4fba0e9e1124b252dd6497a419e7396d. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Failed to save: <h2>Our services aren't available right now</h2><p>We're working to restore all services as soon as possible. Please check back soon.</p>0BZqYagAAAADCHTTC56fSQ7JrorczTCjiUEhMMzBFREdFMDQxMQBFZGdl