public Descriptors.Descriptor getDescriptor() {
        if (descriptor == null) {
            descriptor = buildDescriptor();
        }
        return descriptor;
    }
Gets the descriptor for the Protobuf message.
This method builds a descriptor from the schema definition, potentially using
cached values for better performance.

@return The Protobuf Descriptor for the message
core/src/main/java/kafka/automq/table/deserializer/proto/ProtobufSchemaWrapper.java