Implement human-in-the-loop workflows in Rust with Resonate — durable functions that block on ctx.promise::<T>() until an external actor (webhook, UI, CLI, operator) resolves via resonate.promises.resolve/reject. Use when a Rust workflow step must wait on a decision or data that doesn't come from another worker. Note: ctx.promise is in the SDK (0.6.0) but not yet in rust.mdx.
