Raise every bus user's slow consumer and closed connection as S9, from the bus module's events (hq issue 270, ADR 0357)

The controller heard a slow consumer only on its own connection: the server
says another user's only in its record of closed connections. The bus module
now says that record as events; the watchdogs read the last hour back on every
tick and raise one condition per user and kind, naming the module and machine.
The module check lets the bus module emit, since its tool runner publishes.

cmd/mesh-controller/watchdogs.go

@@ -358,6 +358,14 @@ func (w *watchdogs) gather(ctx context.Context) *signalFacts {
 	}
 	f.advisories = link.Advisories.Since(now.Add(-advisoryQuiet))
 	f.lostConsumers, f.advisoriesErr = w.lostConsumers(ctx, f.advisories)
+	// And what the bus did to every other user's connection, as the bus module said it (novox/hq ADR 0357):
+	// read back for the same hour, and one advisory with the controller's own where both are its.
+	if f.advisoriesErr == nil && w.server != nil && w.js != nil {
+		var faults []link.Advisory
+		if faults, f.advisoriesErr = w.server.BusFaults(ctx, now.Add(-advisoryQuiet)); f.advisoriesErr == nil {
+			f.advisories = link.MergeAdvisories(f.advisories, faults)
+		}
+	}
 	if f.advisoriesErr == nil && w.js != nil {
 		f.deadLetters, f.advisoriesErr = link.HeldDeadLetters(w.js.Context())
 	}