Start in vi navigation mode

Hi. Thanks for prompt-toolkit. It's great.

I'm working on an application that populates the text area and then asks the user to delete parts of it, so the natural way to start is not in InputMode.INSERT but instead in InputMode.NAVIGATION.

I've been playing around with things like this:

    app = Application(
        key_bindings=kb, layout=Layout(root_container), editing_mode=EditingMode.VI
    )
    app.vi_state.input_mode = InputMode.NAVIGATION
    app.run()

But the app still starts in insert mode. I think that Application is calling reset() which is setting it back to insert mode.

Is there a recommended way to do this?

Start by reading Application.reset() in src/prompt_toolkit/application/application.py and the reset logic in src/prompt_toolkit/key_binding/vi_state.py, which the issue identifies as restoring insert mode. Trace the startup sequence and determine how an application can retain InputMode.NAVIGATION; done means the application starts in vi navigation mode after app.run().