DevConsoleCallback

Single-method result callback for the Java-friendly DevConsole.*Async methods (DevConsole.startBrowserAsync, DevConsole.stopAsync, DevConsole.captureScreenshotAsync).

This is a plain fun interface rather than java.util.function.Consumer so the async facade works at minSdk 23 without requiring consumers to enable core-library desugaring (Consumer is API 24). Java callers pass a lambda exactly as before (result -> ...); Kotlin callers use trailing-lambda SAM conversion ({ result -> ... }). Kotlin code should prefer the suspend counterparts.