BellJar: A new framework for testing system recoverability at scale

Introduced BellJar, a new framework for testing system recoverability at scale. BellJar provides an isolated, vacuum-sealed experimentation environment that simulates total infrastructure outages by default, allowing teams to test recovery strategies and identify dependencies. It uses an additive allowlisting scheme to selectively reintroduce necessary production capabilities, enabling granular testing of system startup procedures and validation criteria. BellJar aims to replace tribal knowledge and documentation with codified, repeatable recovery tests deployable in CI/CD pipelines.