Say a walk that waits too long, and a delivery's own stalls (hq ADR 0239)

A walk mesh-delivery never lets go waited for ever with nothing open: S16
says it at 30 minutes, urgent at 4 hours, naming plans go. Phase B: probe
D14 reads the delivery owner's stalled and raises delivery.<id>.stalled,
and H2 takes the table's transition through its close.

cmd/mesh-controller/signals_test.go

@@ -131,6 +131,17 @@ var suppressions = map[string]suppression{
 		inside: func(f *signalFacts) { f.facts.taken = f.now.Add(-47 * time.Hour) },
 		past:   func(f *signalFacts) { f.facts.taken = f.now.Add(-49 * time.Hour) },
 	},
+	// A walk waiting for its delivery's word for 30 minutes (novox/hq ADR 0239).
+	"S16": {
+		inside: func(f *signalFacts) {
+			f.waits = []waitFacts{{id: "plan-2", repository: "novox/app", commit: "c0ffee11", awaits: "mesh-delivery",
+				since: f.now.Add(-29 * time.Minute)}}
+		},
+		past: func(f *signalFacts) {
+			f.waits = []waitFacts{{id: "plan-2", repository: "novox/app", commit: "c0ffee11", awaits: "mesh-delivery",
+				since: f.now.Add(-31 * time.Minute)}}
+		},
+	},
 	// Twice by hand within a fortnight is a healer wanted; once, or the first of two a day too old, is not.
 	"S15": {
 		inside: func(f *signalFacts) {
@@ -524,3 +535,18 @@ func TestALeaseLostOrMissingIsSaid(t *testing.T) {
 		t.Fatalf("serving without the lease was not said: %+v", got)
 	}
 }
+
+// **A walk waiting four hours for its delivery's word is urgent** (S16, novox/hq ADR 0239), and says how on.
+func TestAWalkWaitingFourHoursIsUrgentAndNamesTheWayOn(t *testing.T) {
+	now := time.Date(2026, 10, 6, 12, 0, 0, 0, time.UTC)
+	f := calm(now)
+	f.waits = []waitFacts{{id: "plan-2", repository: "novox/app", commit: "c0ffee11", awaits: "mesh-delivery",
+		since: now.Add(-4*time.Hour - time.Minute)}}
+	got := watchWaits(f)
+	if len(got) != 1 || got[0].Severity != conditions.Urgent || got[0].Key() != "plan.plan-2.waiting" {
+		t.Fatalf("four hours of waiting raised %+v", got)
+	}
+	if !strings.Contains(got[0].Summary, "plans go plan-2") || !strings.Contains(got[0].Summary, "mesh-delivery") {
+		t.Fatalf("it does not say how on: %q", got[0].Summary)
+	}
+}