Record the clarify head and the confidence it replaces (V-661)

CLAUDE.md

@@ -257,6 +257,31 @@ Recall is 15/15 and world is 5/5. Intent is 93.6% mean over three seeds. That is
 **not** comparable to the 76.0% and 84.4% those two arms scored: a softmax has no
 clarify class, so the head's fixture is the 88 cases carrying an intent.
 
+**A fourth head asks instead of guessing, same day** (V-661,
+`docs/evals/2026-08-08-clarify-head-four-head.md`). Clarify is not a value
+of intent, so a softmax cannot emit it. It is a second question over the
+same pooled vector: can Maven act on this at all. That is why the head's
+fixture was 88 cases and not 96. Over three seeds it catches **7.0 of the 8
+`want_clarify` cases and produces 2.3 false clarifies of 88**. The cascade
+today misses 1 and produces 2, so this is parity with no rules in front of
+it. Accuracy is the wrong number here and a head that never asks scores
+91.7%. Confidence is the other half. Max softmax over the intent head reads
+**0.851 where it is right against 0.604 where it is wrong**, ranking right
+above wrong in 83.4% of pairs. `Confidence: 1.0` was a hardcode, and this
+replaces it with a signal. The two are not the same signal: one says which
+intent is unclear, the other says the utterance carries too little to act
+on. **The fourth head is not free the way the third was.** Intent,
+destination and slot F1 each move down one to four points, inside the seed
+spread. `поужинал` is a false clarify on every seed, which is the same
+defect `thinSingleToken` was narrowed for on 2026-08-01.
+
+The corpus for it is generated, because every existing row is answerable by
+construction. **The router-prompt agreement filter cannot work here**, since
+`routeGrammar` has no clarify value and a generated line always agrees with
+itself. A gemma judge replaces it. The first judge called 24 of 40
+answerable rows underspecified, because it judged against a generic
+assistant rather than against Maven's contract.
+
 **Mood is cut, not deferred.** The enum describes her own reply state, not the
 speaker's emotion, and no dataset maps onto it.