improve ux for acting on last duct run

We could export the prefix (or maybe just path to info.json) to an env var or clipboard so the user doesnt have to copy/paste to use `con-duct` against the previous duct run.

Start by locating the CLI handling for acting on the previous duct run and how its info.json path or prefix is currently exposed. Compare exporting a value to an environment variable with copying it to the clipboard, then define which single workflow is supported and verify that con-duct can use the resulting value.

Written by the indexing model from the issue text.