OAK-12331: add an audit event SPI with commit-attached capture and observer drain - #3059

Task org.apache.jackrabbit.oak.commons.concurrent.NotifyingFutureTask@2bee1e47[Not completed, task = org.apache.jackrabbit.oak.spi.commit.BackgroundObserver$1$1@bf350dd] rejected from java.util.concurrent.ThreadPoolExecutor@319fb7f5[Shutting down, pool size = 1, active threads = 1, queued tasks = 0, completed tasks = 6]

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, actions/setup-java@v4, actions/upload-artifact@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/