The OPPO smartphone booth at a megastore in Sao Paulo.Photographer: Maira Erlich/BloombergApple Inc. accused smartphone maker Oppo in a lawsuit of poaching a highly paid member of the Apple Watch team and encouraging him to steal trade secrets for his new job with the Chinese firm.Sensor system architect Chen Shi secretly accessed confidential documents on Apple’s health-sensing technologies for Oppo’s benefit to develop a competing wearable device before departing Apple in June, according to a ...