Constant DEFAULT_HEALTH_PROBE_ENABLED 

pub const DEFAULT_HEALTH_PROBE_ENABLED: bool = true;

Default spec.health.probe.enabled when unset: the periodic backend health probe is ON by default (#345). The probe is the sensor for the repository circuit breaker — with the default onFailure: Degrade, a sustained backend failure moves the repository to Degraded and pauses backups until a re-connect succeeds — so it must run unless the user explicitly opts out with enabled: false. Part of the documented API contract, so it lives here, not in the controller.