expose keychar and forward EVENT_KEY_TYPED

[AucaCoyan]

Hi! Hope you are doing well.

I'm using this library for my application, and when I realized I need to support other keyboards (AZERTY, or non-latin keyboards) I need to use the keychar value from keyboard_event_data , which uiohook.h exposes, but uiohook-napi doesn't.

The benefit of doing this is that with this PR you can:

  const letter = String.fromCharCode(event.keychar);

and have the rendered letter, instead of the keyboard position. This takes dead-key sequences in mind, so ´ + e → é on Spanish/French layouts should work.

As a requirement for the dead key, I need to use EVENT_KEY_TYPED instead of _PRESSED and _RELEASED, because I want to grab the user intention to write é, not the combination of ´ + e pressed and released both.

I did this PR with some help of AI, but read everything I could and simplify as much as possible, I'm not familiar with the project, so sorry if I made a mistake.

Thank you for reading!