Add support for terminal handoff

[ysc3839]

TODO:

• Out-of-process COM register
• Setup conpty ConptyPackPseudoConsole https://github.com/microsoft/terminal/blob/main/src/cascadia/TerminalConnection/ConptyConnection.cpp#L284
• Node.js callback

Issues?
Looks like COM requires a proxy dll to do marshaling. In Windows Terminal this dll is OpenConsoleProxy.dll. We have to ship the proxy dll with this project.

ref: microsoft/terminal#7414, microsoft/terminal#9462

[Tyriar]

It might be convenient to put this here but I think it's is out of scope for node-pty. I also don't really want to merge and accept ownership over something we don't use and therefore cannot properly maintain.

[ysc3839]

node-pty does not support passing a HPCON and get an ITerminal in js.
So in order to make terminal handoff works, I still have to modify node-pty to add such interface.
And terminal handoff requires OpenConsole.exe and conpty.dll, which are both available in node-pty package.
So I think the best solution is to add terminal handoff support in node-pty.

something we don't use

I think third-party electron-based terminals do need such feature. They are waiting for Microsoft to provide docs, libs and examples.

cannot properly maintain

Both Windows Terminal and node-pty are Microsoft's project. I don't think it's hard to maintain.

[Tyriar]

Both Windows Terminal and node-pty are Microsoft's project. I don't think it's hard to maintain.

I maintain this, another team in another department maintains microsoft/terminal. It's not a question of whether someone at Microsoft could maintain it effectively, it's a question of whether I can. I only say this because I've run into exactly this problem before where we merged things we didn't use/understand into xterm.js and they eventually degraded and broke and caused problems when trying to make changes down the road.

node-pty does not support passing a HPCON and get an ITerminal in js.
So in order to make terminal handoff works, I still have to modify node-pty to add such interface.
And terminal handoff requires OpenConsole.exe and conpty.dll, which are both available in node-pty package.

If we need to expose some more things in the API to achieve this we can do that. Then we have a simple contract that we just need to make sure works across releases.

I think third-party electron-based terminals do need such feature. They are waiting for Microsoft to provide docs, libs and examples.

Maybe some day (after microsoft/vscode#34442), but in its current state we wouldn't want to have VS Code as a possible default.

[ysc3839]

Thank you. I will make this a standalone project. And I will modify this PR to include only API to construct ITerminal from in/out pipes.