feat(gl): add standalone ledger authority mode

application/health/service.go

@@ -15,6 +15,10 @@ type SettlementMonitor interface {
 	Stats(context.Context) (ledger.SettlementStats, error)
 }
 
+type SettlementAuthority interface {
+	SettlementAllowed(context.Context) (bool, error)
+}
+
 type Status struct {
 	Serving           bool
 	DatabaseReady     bool
@@ -50,6 +54,10 @@ func (s *Service) Check(ctx context.Context) Status {
 		if err == nil {
 			status.SettlementStats = stats
 			status.SettlementReady = true
+			if authority, ok := s.settlement.(SettlementAuthority); ok {
+				allowed, authorityErr := authority.SettlementAllowed(ctx)
+				status.SettlementReady = authorityErr == nil && allowed
+			}
 		}
 	}
 	return status

application/health/service_test.go

@@ -61,3 +61,15 @@ func TestCheckReportsSettlementQueryFailure(t *testing.T) {
 		t.Fatalf("unexpected status: %+v", got)
 	}
 }
+
+type pausedSettlementStub struct{ settlementStub }
+
+func (pausedSettlementStub) SettlementAllowed(context.Context) (bool, error) { return false, nil }
+
+func TestGLOnlyKeepsLedgerServingWhileNormalSettlementClientsFailClosed(t *testing.T) {
+	monitor := pausedSettlementStub{settlementStub{stats: ledger.SettlementStats{Pending: 3}}}
+	got := NewService(databaseStub{}, monitor).Check(context.Background())
+	if !got.Serving || !got.DatabaseReady || !got.SettlementEnabled || got.SettlementReady || got.SettlementStats.Pending != 3 {
+		t.Fatalf("unexpected GL-only readiness: %+v", got)
+	}
+}