Apple Inc. has halted work on a project to build an iPhone hardware subscription service, according to people familiar with the matter, retreating from an attempt to change the way consumers buy its flagship device.The idea was to make owning an iPhone like subscribing to an app — with consumers paying monthly fees and getting new phones each year — but Apple recently wound down the effort, according to people familiar with the matter. The team was disbanded and reassigned to other projects, sai...