Your first week on a mobile AI repo usually starts with a task that sounds small: point the app at a different inference backend so you can test without touching production credentials. On a mid-range Android phone in a debug build, with the screen off for thirty seconds and Wi-Fi dropping to LTE mid-request, that "small" task is where juniors either learn the repo or quietly break it. The drill below turns that task into a repeatable swap with evidence, and it fits the first hour, first PR, fir...