Requires a this ghostty PR with the clipboard_set effect to be merged: https://github.com/ghostty-org/ghostty/pull/13182
Bind the GHOSTTY_TERMINAL_OPT_CLIPBOARD_SET effect: WithClipboardSet option, SetEffectClipboardSet live setter, and the C trampoline following the existing effect patterns. The handler receives the OSC 52 kind byte and the undecoded base64 payload; read requests never reach it.21