Keep main's rule for which haves run inside the node's own composition

Review round 1: a have naming no build in a phase but running is also written for a
module that runs inside the node's own (waiting for a yes), so taking it out would
drop its resources before the yes. The fp the held have now keeps already fixes
postgres (issue 1289); a test drives an interrupted backup end to end.

Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL

internal/agent/agent_test.go

@@ -591,6 +591,27 @@ func TestADataModuleIsBackedUpFirstAndHeldWhenItFails(t *testing.T) {
 		return h.Phase == string(delivery.PhaseRunning) && h.FP == fp2 && h.Composed == dig2
 	})
 
+	// The node agent stopped while the backup ran, the module known only from its have: the held have names what runs
+	// and says it was interrupted (postgres on novox, 2026-10-31, held naming nothing).
+	ib := newBed(t)
+	ib.comps.before(ck1, craw1)
+	ib.comps.before(ck2, craw2)
+	iwk, iwraw := wantFor(t, "db", fp2, dig2, delivery.BackupAgain)
+	ib.wants.before(iwk, iwraw)
+	ib.haves.stored = map[string]Have{"db": {Module: "db", FP: fp1, Composed: dig1, Phase: string(delivery.PhaseRunning)}}
+	began := make(chan struct{})
+	ib.env.Backup = func(ctx context.Context, _ string) Backup {
+		close(began)
+		<-ctx.Done()
+		return Backup{Words: "the backup's ask was cancelled"}
+	}
+	stopI := ib.run()
+	<-began
+	stopI()
+	if h := ib.haves.last("db"); h.Phase != string(delivery.PhaseHeld) || h.FP != fp1 || h.Composed != dig1 || h.Detail != BackupInterrupted {
+		t.Errorf("held after an interrupted backup: %+v", h)
+	}
+
 	// At a start: a backup the node agent's own stop interrupted (postgres on novox, 2026-10-31) is no failure, so it is
 	// backed up again and applied while the want asks a backup; a backup that failed stays held for the operator.
 	for _, row := range []struct {