Page events in a native embedded app

In a .NET MAUI embedded app, you need to add code to light up the `Appearing` and `Disappearing` events on `Page`. The native embedding doc should be updated to reflect this.

More info: https://github.com/dotnet/maui/issues/11281#issuecomment-2075466755

Start with the native embedding documentation and the linked issue comment for the expected behavior. Identify where the embedded app's Page lifecycle is described or implemented; done means the Appearing and Disappearing events are enabled and the documentation accurately explains how to use them.

Written by the indexing model from the issue text.