Nx.Serving for the D4 NLI entailment verifier: a Bumblebee.Text.text_classification
serving over a dedicated MNLI cross-encoder. Input is {premise, hypothesis} string pairs
(evidence, clause); output is per-label softmax scores, from which
EntailmentVerifiers.Bumblebee reads the entailment probability.
Started (like Foresight.ML.RerankerServing) only when the NLI verifier is in use — i.e.
a :entailment_serving_name is configured. Mirrors the reranker serving's structure.