native-messaging app example: provide non-contrived example for each platform

[minfrin]

What information was incorrect, unhelpful, or incomplete?

The native messaging example provides a contrived app that bounces a message back as follows:

https://github.com/mdn/webextensions-examples/tree/main/native-messaging/app

This example is useless in the real world, where any useful extension is expected to interact with the end user in some way.

In windows specifically, finding an example of a gui application that can read and write to the console is very difficult, and finding examples of native messages apps for windows is also very difficult.

What did you expect to see?

A useful example of a native messaging app for the main supported programs, doing a real world task like printing a message in a dialog box on a screen.

This is particularly important for windows, where examples are almost impossible to find, and documentation has large gaps.

Do you have any supporting links, references, or citations?

No response

Do you have anything more you want to share?

No response

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