Judge the take-in's stall by keys settled with work to do, and clear its alarms after a restart (issue 1945, ADR 0544, review 2)

A refused key stays unacknowledged during its delay, so one waiting key on a
quiet mesh raised take-in-stalled, cleared at the next ack and raised again.
The watch now counts the keys the loop settled (acknowledged or refused, as
the bus took them) and calls it a stall only with work to do, keys not
delivered yet or a batch handed and not settled, and nothing settled for 5
minutes: a hung loop stays loud. Its first look always says what it found, so
a stall raised before a restart is cleared once this controller moves. A
consumer not made raises take-in-not-consumed under its own id per bucket,
cleared when that consumer is made. Acks are synchronous, so only those the
bus took count; on stop the iterator is drained and what it held, and a batch
cut by the stop, are refused with no delay.
Research 072: the take-ins on a bounded pull consumer.

cmd/mesh-controller/plain_words.go

@@ -77,6 +77,13 @@ var plainWordings = map[string]func(conditions.Observation) words{
 				"five minutes while builds wait. Until it moves, no new build reaches a machine; the details say how many wait.",
 			Resolved: "new builds are being prepared again"}
 	}),
+	// A bucket of done keys whose take-in consumer could not be made (take_in_consumer.go, novox/hq ADR 0544 §6).
+	kindTakeInNotConsumed: worded(func(o conditions.Observation) words {
+		return words{Headline: "Some new builds are not being prepared",
+			Explanation: "The mesh could not start reading one of the two places new builds are announced in, so the " +
+				"builds announced there wait until the controller starts again. The details say which and why.",
+			Resolved: "the mesh reads where new builds are announced again"}
+	}),
 	// Machines and their node-engine.
 	"silent": worded(func(o conditions.Observation) words {
 		m := machineOr(o, "a machine")