Recognize Keycloak REGISTER events in event log

[kberzinch]

Adds an elif branch in get_events so that Keycloak user events of type REGISTER (emitted when an account is provisioned via an identity provider broker, e.g. CAS into the workspace-onboarding client) are rendered in the event log instead of bubbling up as Unrecognized type in Keycloak event.

The new branch mirrors the format of the existing LOGIN / LOGOUT / LOGIN_ERROR / LOGOUT_ERROR handlers and produces a description like registered through workspace-onboarding.

Testing

• poetry run black --check checkpoint.py
• poetry run flake8 checkpoint.py
• poetry run pylint checkpoint.py
• poetry run mypy --strict --scripts-are-modules checkpoint.py
• Ran a standalone simulation of the if/elif chain with the sample event from the task description and confirmed the description resolves to registered through workspace-onboarding.

End-to-end manual reproduction of a REGISTER event would require a Keycloak identity-provider broker (CAS) connected to a real GT account, which is not reachable from the cloud VM. The change is a 2-line additive branch matching the existing patterns and all linters pass.