feat(divergence): Jev noul restatement check -> harness review nudge (#25)

nestapi.go

@@ -184,6 +184,10 @@ func (s *Server) postNestMessage(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	if kind == "deliver" {
+		go s.checkDivergence(nest, record)
+	}
+
 	writeJSON(w, http.StatusCreated, nestRecord(record))
 }
 
@@ -298,6 +302,42 @@ func (s *Server) respondOne(nest Nest, req Message, crow string, lens bool) {
 	}
 	if record, err := s.msgs.Append(reply); err == nil {
 		s.emitNestMessage(record)
+		if record.Kind == "deliver" {
+			s.checkDivergence(nest, record)
+		}
+	}
+}
+
+// checkDivergence asks Jev whether this deliver restates earlier delivers that
+// answer the same request. Above the band the crow gets a review nudge; the
+// deliver itself stays in the log (nudges never silence).
+func (s *Server) checkDivergence(nest Nest, m Message, budgets ...*Budget) {
+	if m.Kind != "deliver" {
+		return
+	}
+	earlier := s.msgs.EarlierDelivers(nest.ID, m.RefersTo, m.ID)
+	if len(earlier) == 0 {
+		return
+	}
+	if _, nudged := s.msgs.NudgeFor(nest.ID, m.MsgID()); nudged {
+		return // one nudge per deliver; no loop
+	}
+	prob, ok := s.p.Flock.ClassifyDivergence(s.ctx, map[string]any{"this": m.Text, "earlier": earlier}, budgets...)
+	if !ok || prob < s.p.Flock.jev.threshold {
+		return
+	}
+	nudge := Message{
+		NestID:    nest.ID,
+		Kind:      "nudge",
+		Author:    "harness",
+		Text:      "This reads like a point already made in the thread; review the earlier delivers and add your distinct angle or let it rest.",
+		To:        m.Author,
+		RefersTo:  m.MsgID(),
+		TaggedBy:  "harness",
+		Timestamp: time.Now().UTC().Format(time.RFC3339),
+	}
+	if record, err := s.msgs.Append(nudge); err == nil {
+		s.emitNestMessage(record)
 	}
 }