The Room Migration Mistake That Crashed Every User's App

I crashed every existing user of my QR scanner app with one bad Room migration — added a label field, bumped the schema version, shipped, and watched the launch graph die. Below is everything I do now to avoid that, plus the entity/DAO/ViewModel patterns that turn Room from another framework chore into the fastest way to ship structured data on Android. I shipped my first QR scanner app without scan history. Users complained. Fair enough - scanning the same WiFi QR code every time is annoying. S