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.

internal/broker/bus_module_emits_test.go

@@ -0,0 +1,34 @@
+package broker
+
+import (
+	"slices"
+	"testing"
+)
+
+// **The bus module's watch speaks through the runtime that carries it** (novox/hq ADR 0357): the node's
+// runtime is granted the events the bus module declares, under the module's name, while the bus's own
+// account keeps the snapshot API and nothing else (ADR 0235).
+func TestTheRuntimeCarryingTheBusModuleMayPublishItsEventsAndTheBussAccountMayNot(t *testing.T) {
+	events := []string{"bus.slow-consumer", "bus.connection-closed"}
+	runtime := Principal{Kind: KindNodeTools, Node: "anchor", Module: RuntimeModule,
+		Carries: []Declared{{Module: "nats", Emits: events}}}
+	p, err := PermissionsFor(runtime)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, e := range events {
+		if !slices.Contains(p.Publish, "mesh.mod.nats.event."+e) {
+			t.Errorf("the runtime carrying the bus module may not publish %s: %v", e, p.Publish)
+		}
+	}
+	account := Principal{Kind: KindModule, Node: "anchor", Module: "nats", Emits: events, SnapshotsTheBus: true}
+	a, err := PermissionsFor(account)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, s := range a.Publish {
+		if s == "mesh.mod.nats.event.bus.slow-consumer" || s == "mesh.mod.nats.event.bus.connection-closed" {
+			t.Errorf("the bus's own account is granted %s", s)
+		}
+	}
+}