I am trying to implement a security rule in Micronaut 4.5.0 like so:

package test;

import static io.micronaut.security.utils.LoggingUtils.debug;

import io.micronaut.context.annotation.Requires;
import io.micronaut.core.annotation.Nullable;
import io.micronaut.security.authentication.Authentication;
import io.micronaut.security.rules.IpPatternsRule;
import io.micronaut.security.rules.SecurityRule;
import io.micronaut.security.rules.SecurityRuleResult;
import jakarta.inject.Singleton;
import java.io.IOException;
import java.net.http.HttpRequest;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import java.util.Objects;
import org.bouncycastle.crypto.util.PublicKeyFactory;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.reactivestreams.Publisher;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.publisher.Mono;


@Requires(classes = HttpRequest.class)
@Singleton
public class SignatureHeaderSecurityRule implements SecurityRule<HttpRequest> {

  private final int ORDER = IpPatternsRule.ORDER - 100;
  private final PublicKey incomingPublicKey;
  private static final Logger LOG = LoggerFactory.getLogger(SignatureHeaderSecurityRule.class);

  public SignatureHeaderSecurityRule(
      Configuration configuration
  ) throws IOException {
    incomingPublicKey = (PublicKey) PublicKeyFactory.createKey(
        Objects.requireNonNull(SignatureHeaderSecurityRule.class.getResourceAsStream(
            configuration.getIncomingPublicKey())));
  }

  @Override
  public Publisher<SecurityRuleResult> check(
      @Nullable HttpRequest request,
      @Nullable Authentication authentication
  ) {
    try {
      Signature signer = Signature.getInstance(
          "SHA256withRSA",
          BouncyCastleProvider.PROVIDER_NAME);
      signer.initVerify(incomingPublicKey);
      String signatureHeader = request.headers().firstValue("Signature").orElse("");
      boolean verification = signer.verify(signatureHeader.getBytes(StandardCharsets.UTF_8));
      if (verification) {
        return Mono.just(SecurityRuleResult.ALLOWED);
      } else {
        return Mono.just(SecurityRuleResult.REJECTED);
      }
    } catch (SignatureException e) {
      debug(LOG, e.getMessage());
      return Mono.just(SecurityRuleResult.REJECTED);
    } catch (NoSuchAlgorithmException | NoSuchProviderException | InvalidKeyException e) {
      debug(LOG, e.getMessage());
      return Mono.just(SecurityRuleResult.UNKNOWN);
    }
  }

  @Override
  public int getOrder() {
    return ORDER;
  }
}

I have configured my URI map like so:

micronaut.security.enabled=true
micronaut.security.authentication=bearer

micronaut.security.intercept-url-map[0].pattern=/notify
micronaut.security.intercept-url-map[0].http-method=POST
micronaut.security.intercept-url-map[0].access[0]=isAnonymous()

I have tried to step-debug into the rule and/or add logging. However, my custom security rule is never called. In my understanding this is all that is necessary to kick off a custom security rule in Micronaut.
How exactly do I need to configure the rule to be executed?