Better support for human-in-the-loop

[ianmacartney]

Currently, to do human-in-the-loop workflows, you can use the AI SDK pattern where you pass in a tool without an execute function. When the tool call happens, it won't continue and the resulting message will be the tool call.
You then save that somewhere that the client has a query on, and when the client submits some data, you can re-execute the thread with the tool response to continue.

If you're doing this as part of a workflow using the Workflow component, however, it's not possible to suspend execution to wait. To have that work, we'll need Pause/Resume

[ianmacartney]

I'm going to add examples soon on how to do this, but punt on doing pause/resume until there's pent-up demand, as things in milestone 2 seem more important