Essentially I'd like to build a docker image of code from a repository, and deploy and run it, and manage its lifecycle. Perhaps I could copy the CF template from the Copilot to do the same.
Presumably, you're running it based on some input. Jobs are the right paradigm if this input is periodic (for example, processing a batch of items in S3 every few hours).
Otherwise, you may want to consider a Worker: https://aws.github.io/copilot-cli/docs/concepts/services/#wo... which can be connected to an SQS queue and activated by publishing messages to the queue.
Lifecycle management is a matter of using the delete commands:
svc delete
job delete
env delete
app delete
https://aws.github.io/copilot-cli/docs/commands/app-delete/
Hope that helps!