Provider-agnostic judgment trait and wire types for polychrome.
A judgment is a typed decision over a state: a yes/no probability
([Question::Noul]) or one option from a closed set
([Question::Choice]). A judgment model returns probabilities, never
generated text, so code can threshold and combine the answers without
parsing prose.
[JudgmentProvider] is the seam between a decision site and any concrete
backend, the same way polyc_llm::LlmProvider is for completions: one
implementation crate per backend, dispatched behind [DynJudgment]. The
core never names a vendor.