How tightly integrated are Prefect and Control flow? How do prefect.task/cf.task and prefect.flow/cf.flow relate to each other? From what I have read, I get the impression that a cf flow is kind of just a fungible docker image that gets deployed to a prefect work pool? and thus we could swap out the AI agent framework with something else like Langgraph and just use Prefect as a higher level management tool of the fleet of agents?

yes!

we could swap out the AI agent framework with something else like Langgraph and just use Prefect as a higher level management tool of the fleet of agents?