engine+cli: enabled-events introspection

[fruwe]

Implement enabled_events per the spec (fruwehq/harel §14): Host.enabled_events(instance) / Instance.enabled_events() returning the sorted declared events the active configuration handles (leaf-up + orthogonal; exclude reserved lifecycle events). Add harel enabled <inst> [--json], include it in inspect, and wire expect.enabled into the conformance harness. Unit tests + bump conformance pin. v0.0.4.