Behaviour for grading a single rubric criterion against a transcript (spec §4).
Given one rubric criterion (the keyword key, e.g. :covers_pitfall), its
description (what a good call/transcript must satisfy), and the transcript
the paired Noizu.MCP.Eval.Runner produced, a judge returns a grade:
%{pass: boolean(), score: float(), notes: binary()}pass gates the harness (and mix noizu.mcp.eval --gate); score and notes
are recorded in the report for triage.
Select the active judge via the :noizu_mcp :eval_judge application env; it
defaults to Noizu.MCP.Eval.Judge.Stub. Real LLM-as-judge adapters are
app-layer follow-ups.