BackgrounderInitializer
androidx.startup initializer that populates BackgroundTaskManager.shared before Application.onCreate runs. Registered in the library's manifest, so a consumer that keeps the InitializationProvider gets it for free.
Only constructs the instance. Registering workers and calling start() stay in Application.onCreate, because the registry seals at start() and must see every registration first. Nothing here touches WorkManager: the ephemeral sweep runs inside start(), after Configuration.Provider has had its chance to install our WorkerFactory.
Idempotent with an explicit BackgroundTaskManager.configure(application) call — whichever runs first wins.