Function apply_teleport_registration 

pub(super) fn apply_teleport_registration(
    config: &Config,
    mz: &Materialize,
    service: &mut Service,
)

Adds the Teleport discovery labels and annotations to service when --enable-teleport-registration is set. A no-op otherwise, which is the rollback path: without the flag, this function changes nothing about the Service.

A Service the agent would reject is left unannotated rather than annotated and silently dropped, so the reason reaches our own logs instead of only the agent’s.