mesh-knowledge: ask changes in the review for a decision nothing would cite, so its acceptance never turns the module unhealthy (hq issue 504)

The whole-set rule cited ran only after acceptance: the review approved a
decision with no home and no record linking it, the rule then failed, and
the module's health turned red for a fault its author could only repair
after the fact. hq held the rule at the record's own merge. The review now
judges it ahead, before the judgement: such a decision stays proposed with
a changes finding naming the rule. It is not refused at propose, because
no record can link a number only reserved.

modules/mesh-knowledge/cmd/mesh-knowledge/rules.go

@@ -546,6 +546,36 @@ func JudgeSet(records []*Record) []Finding {
 	return out
 }
 
+// UncitedOnAcceptance is the whole-set rule `cited` judged ahead, on a decision's working version as it would
+// stand once accepted, over the records as JudgeSet reads them: "" when it names a home or a record accepted (or
+// superseded) links it, else what the rule would say. hq held this rule at the merge of the record's own pull
+// request, which carried the design citing it; the knowledge base holds it in the review, before the judgement, so
+// an acceptance never leaves a decision cited by nothing (novox/hq issue 504). It is not refused at propose: no
+// record can link a number only reserved, so a record that will cite a new one is proposed after it, accepted, and
+// the new one proposed again. A citing record changed by a correction after the acceptance is what the rule, run
+// after every acceptance, still says. An imported record was held to hq's checks, and its correction is not judged
+// here, as JudgeSet does not judge it.
+func UncitedOnAcceptance(r *Record, all []*Entry) string {
+	if r.Kind != KindDecision || len(r.Homes) > 0 || (r.Pending != nil && r.AcceptedAt.IsZero()) {
+		return ""
+	}
+	k := r.Key()
+	for _, e := range all {
+		from := e.Current
+		if from.Key() == k || !(from.Accepted() || from.Status == StatusSuperseded) {
+			continue
+		}
+		for _, l := range from.Links {
+			if to, ok := l.To.Record(); ok && to == k {
+				return ""
+			}
+		}
+	}
+	return fmt.Sprintf("%s would be accepted with nothing citing it: it names no home and no accepted record links it. Name "+
+		"its home (homes: the hq design or playbook that cites it), or have the record that links it accepted first; then "+
+		"propose this one again", k)
+}
+
 // RuleFrom is the day each dated rule began to hold a record, as hq's checks hold it: a record dated earlier was
 // never held to it, and a dated correction of it (a progressive insight, which keeps the record's date) is not.
 // words.py held the retired words from 2026-10-07 and the daemons' lines from 2026-10-09; cycle.py the deferrals