OSC 52 clipboard relay

[MichaelCosby]

This one I'm not really sure about. It makes Claude's "copy to clipboard" command work. It may be duplicative of the copy & trim plugin, and it's possible the way it works violates your "never mess with the input & output from the client" rule. i can absolutely understand if you don't want to make the change, and it's a very small patch so I don't mind just having it in my branch, too, but I figured I'd offer it up.