Huawei figured out which hand you're holding the phone with by reading the damage your palm does to the cell signal. When you grip a phone, your hand blocks part of the antenna and attenuates it. Back in 2010, this exact physics was Apple's biggest scandal. iPhone 4 owners bridged the antenna band with their palm, bars dropped, and Steve Jobs told everyone to just avoid holding it that way. Apple ended up giving free cases to every buyer. Huawei turned the same physics into a sensor. A…