Apple Inc. has lost its fourth AI researcher in a month to Meta Platforms Inc., marking the latest setback to the iPhone maker’s artificial intelligence efforts.Bowen Zhang, a key multimodal AI researcher at Apple, left the company on Friday and is set to join Meta’s recently formed superintelligence team, according to people familiar with the matter. Zhang was part of the Apple foundation models group, or AFM, which built the core technology behind the company’s AI platform....