[Feature request] Exit / close function for code apps (like Power Fx Exit()) #498

Describe the bug

Canvas apps can return the user to the app list with Exit() (and sign out with Exit(true)). Code apps have no equivalent: @microsoft/power-apps 1.5.0 only offers getContext, setConfig, data access and telemetry. Inside the player the app is a cross-origin iframe, so it can't close itself or navigate the host.

Request: add exit(options?: { signOut?: boolean }) to @microsoft/power-apps/app that asks the host to close the app — in the Power Apps mobile app back to the app list, in the browser player the same behaviour as canvas Exit().

Why: mobile-first code apps (bottom navigation) need an explicit "Exit app" action; the Android back button walks back page by page through the app's history first. Shared devices need Exit(true) for sign-out.

Environment information

• pa 1.3.0, @microsoft/power-apps 1.5.0, Power Apps Android app.
• CodeApp used via Power Apps Android Mobile App