feat: Custom Click Action API

[bluegreensea]

Custom click action packet parse and event API.

The Test used refCnt not exists, I am not sure the Test still correct or not.

[roccodev]

Shouldn't there be a way to consume the action on the proxy without forwarding it to the backend? Say for example for click prompts sent by the proxy

Granted it probably won't hurt to still send it to the backend, but there is a chance another conflicting action is registered there

I'm also wondering whether you could also build a callback/future-based prompt API, or whether that is better suited for plugins to handle

[bluegreensea]

The first thing is done.

Can I ask what the exactly mean for callback/future-based prompt API?