Under the hood
Session-event signing now delegates to an external signer instead of signing locally with an in-process key
What
Session events used to be signed synchronously using Node's built-in cryptography library with a raw private key held in the process. Signing is now asynchronous and delegates the actual signing operation to an injected signer object, rather than performing the cryptographic signature in-process against local key material.
Why
Moving signing to a delegated, asynchronous signer means the private key material no longer needs to live directly in the process doing the signing, which can support setups where signing happens through a separate, more controlled component.