Add Kino.JS.Live events support to subscribe/unsubscribe

[hugobarauna]

This will be useful, for example, for using custom kino in "custom form", like this one: https://gist.github.com/hugobarauna/0150a90009f737e6949c9285f34329de

So users could build something like this:

Here's the code for this example: https://gist.github.com/hugobarauna/a8adeb29d67ee7dda54da8f75a82274f

[Copilot]

Pull Request Overview

This PR extends the Kino.Control subscription functionality to support Kino.JS.Live events, enabling users to subscribe to and unsubscribe from custom interactive components. This enhancement allows for building interactive custom forms and components that can communicate events back to the Elixir process.

• Updated subscribe/2 and unsubscribe/1 functions to accept Kino.JS.Live.t() structs
• Modified function documentation to reflect the new JS.Live events support
• Added comprehensive test coverage for the new Kino.JS.Live subscription functionality

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
lib/kino/control.ex	Extended subscribe/unsubscribe functions to support Kino.JS.Live structs and updated documentation
test/kino/control_test.exs	Added test case verifying subscription to Kino.JS.Live events works correctly