WASHINGTON/DETROIT (Reuters) – The confession of cheating that’s embroiled Volkswagen AG (VOWG.DE) in one of the biggest scandals in auto industry history came on a cool California morning, on the sidelines of an academic conference focused on green transportation. After more than a year of stonewalling investigators, Volkswagen stunned two senior officials with the U.S. Environmental Protective Agency and California’s environmental watchdog by admitting the automaker hacked its own cars to deceive U.S. regulators about how much their diesel engines pollute.