Name the bus upgrade as the mesh call a person makes, and say a same-source rebuild needs no step (review of #173)

The condition and the plan named the verb in command-line form; the operator reaches it through the mesh
MCP server, so it is written as that call. A rebuild of the same source moves nothing (issue 280), which
the plan cannot know before the build, so its line says so.

cmd/mesh-controller/bus_waits.go

@@ -128,8 +128,9 @@ func (b busFacts) heldByTheBus() map[string]bool {
 	return out
 }
 
-// busUpgradeVerb is the verb that ends the wait, as the summary names it.
-const busUpgradeVerb = "`mesh-controller.bus upgrade --why … --reversible|--irreversible`"
+// busUpgradeVerb is the call that ends the wait, as the summary names it: through the mesh MCP server, with
+// why, saying whether the new version can be undone ("reversible": "true") or not ("irreversible": "true").
+const busUpgradeVerb = "`mesh_call mesh-controller.bus {\"upgrade\": \"true\", \"why\": \"…\", \"reversible\" or \"irreversible\": \"true\"}`"
 
 // watchBusWaits is S17: a send held for the bus's planned step, said at once to the operator.
 func watchBusWaits(f *signalFacts) []conditions.Observation {

cmd/mesh-controller/bus_waits_test.go

@@ -112,8 +112,8 @@ func TestASendHeldForTheBusStepIsSaidAtOnceAndNotAsLateness(t *testing.T) {
 	if o.Key() != "bus.nats.step-waiting" || o.Kind != kindBusStepWaiting || o.Resolver != conditions.ResolverOperator {
 		t.Fatalf("raised %s (%s), resolver %q", o.Key(), o.Kind, o.Resolver)
 	}
-	for _, want := range []string{"anchor", "mesh-host", "88135ad0", "32307bd1", "mesh-controller.bus upgrade --why",
-		"--reversible", "--irreversible", "2026-10-08T18:29:00Z", "plan-1"} {
+	for _, want := range []string{"anchor", "mesh-host", "88135ad0", "32307bd1", "mesh_call mesh-controller.bus",
+		`"upgrade": "true"`, `"reversible"`, `"irreversible"`, "2026-10-08T18:29:00Z", "plan-1"} {
 		if !strings.Contains(o.Summary, want) {
 			t.Errorf("its summary does not say %q: %s", want, o.Summary)
 		}

cmd/mesh-controller/changeplan.go

@@ -55,7 +55,8 @@ func changePlanOf(repository, base, head string, r mergeReach, entries []invento
 				// Said before the merge (novox/hq issue 336): a new bus build holds every send to the bus's machine
 				// until a person takes the step, so merging it is a promise to take it.
 				p.Steps = append(p.Steps, fmt.Sprintf("%s: %s is never sent by an ordinary send, and until %s runs, "+
-					"nothing else is sent to %s either", busUpgradeNeeded, name, busUpgradeVerb, strings.Join(e.On, ", ")))
+					"nothing else is sent to %s either — unless the new build turns out the same as the one running there "+
+					"(issue 280)", busUpgradeNeeded, name, busUpgradeVerb, strings.Join(e.On, ", ")))
 			case name == "nats" || catalogue.ProvidesBus(e.Manifest):
 				p.Steps = append(p.Steps, "a planned bus step: the bus is upgraded by `bus upgrade`, never by an ordinary send")
 			case waits && len(e.On) > 0:

cmd/mesh-controller/changeplan_test.go

@@ -61,7 +61,7 @@ func TestAChangePlanSaysWhatEachMachineReceives(t *testing.T) {
 	// Said before the merge (novox/hq issue 336): merging it holds every send to the bus's machine until a
 	// person runs the bus's step, and the verb that does.
 	for _, want := range []string{"merging this needs a person's bus upgrade", "nothing else is sent to anchor",
-		"`mesh-controller.bus upgrade --why … --reversible|--irreversible`", "photos waits for a person",
+		"mesh_call mesh-controller.bus", "the same as the one running there", "photos waits for a person",
 		"nats provides mesh-bus"} {
 		if !strings.Contains(text, want) {
 			t.Errorf("the steps do not say %q:\n%s", want, text)