cmd/cli: ensure ctrld was uninstalled before installing

In some old Windows systems, s.Uninstall does not remove the service
completely at the time s.Install was running, prevent ctrld from being
installed again.

Workaround this by attempting to uninstall ctrld several times, re-check
for service status after each attempt to ensure it was uninstalled.

cmd/cli/cli.go

@@ -266,7 +266,7 @@ func initCLI() {
 			tasks := []task{
 				{s.Stop, false},
 				{func() error { return doGenerateNextDNSConfig(nextdns) }, true},
-				{s.Uninstall, false},
+				{func() error { return ensureUninstall(s) }, false},
 				{s.Install, false},
 				{s.Start, true},
 				// Note that startCmd do not actually write ControlD config, but the config file was
@@ -2102,3 +2102,17 @@ func checkDeactivationPin(s service.Service) error {
 	mainLog.Load().Error().Msg("deactivation pin is invalid")
 	return errInvalidDeactivationPin
 }
+
+// ensureUninstall ensures that s.Uninstall will remove ctrld service from system completely.
+func ensureUninstall(s service.Service) error {
+	maxAttempts := 10
+	var err error
+	for i := 0; i < maxAttempts; i++ {
+		err = s.Uninstall()
+		if _, err := s.Status(); errors.Is(err, service.ErrNotInstalled) {
+			return nil
+		}
+		time.Sleep(time.Second)
+	}
+	return errors.Join(err, errors.New("uninstall failed"))
+}