Does Catalyst support long-running workflows that span days or weeks?

Yes, Catalyst supports workflows of arbitrary duration, from seconds to weeks or longer. State is persisted durably, so workflows survive infrastructure restarts and can be paused or suspended. There is no built-in timeout for workflow lifetime, but you should design for idempotent activities and handle timeouts within your workflow logic. Catalyst's replay mechanism efficiently handles long pauses by resuming from the last checkpoint.