Name the fill condition for buckets and logs, and judge each one on its own

Review of #231: "store" is the glossary's word for the postgres server, so
the condition is bucket-or-log-filling. And one stream that cannot be read
no longer fails the whole check: it is said as unread with its reason, an
open fill condition for it is kept, and every other bucket and log is
still judged (ADR 0297 §6).

cmd/mesh-controller/plain_words.go

@@ -606,12 +606,18 @@ var plainWordings = map[string]func(conditions.Observation) words{
 			Explanation: "The bus refused messages from a part of the mesh, so what they carried did not happen.",
 			Resolved:    "Resolved: the bus takes the messages again"}
 	}),
-	kindStoreFilling: worded(func(o conditions.Observation) words {
-		return words{Headline: "A module's store on the bus is filling up",
+	kindBucketOrLogFilling: worded(func(o conditions.Observation) words {
+		return words{Headline: "A module's bucket or log on the bus is filling up",
 			Needs: "decide whether to raise its cap or have the module keep less.",
 			Explanation: "A bucket or log a module keeps on the bus holds three quarters of its cap or more. When it " +
 				"is full, the bus refuses what the module writes there.",
-			Resolved: "The store has room again"}
+			Resolved: "It has room again"}
+	}),
+	kindBucketOrLogUnread: worded(func(o conditions.Observation) words {
+		return words{Headline: "A module's bucket or log could not be read",
+			Explanation: "The controller could not read how full a bucket or log a module keeps on the bus is, so it " +
+				"cannot say whether it is filling up. It asks again at its next check.",
+			Resolved: "It can be read again"}
 	}),
 	"stream-wrong": worded(func(o conditions.Observation) words {
 		return words{Headline: "Part of the bus's storage is wrong",