Pre-flight and post-flight — the service layer beneath two new review stages

augment-it is growing two new pipeline stages: a request-reviewer that shows you exactly what is about to be sent to the model, and a response-reviewer that lets you triage what came back. This entry is the service layer beneath both — the no-UI plumbing. Its load-bearing idea is small and strict: there is now exactly one function that assembles a model request, so the request you preview is byte-identical to the request that fires. Alongside it, a new response-store service turns every fired response from a throwaway cell into a first-class object you can inspect and flag. The two frontends that sit on top are their own story — coming next.