Swagger Api Synchronization

# Set up an OpenAPI spec-sync workflow in this project I want the same backend-spec workflow I use in another repo: a script that diffs the live OpenAPI spec against a local snapshot and writes a **frontend-oriented** change report, plus a `/api-sync` slash command that turns that report into a phased plan. Fill these in from the repo before you start (ask me only if you can't work it out): - **Spec source**: find it yourself — see Part 0. Don't ask me for the URL until you've looked. Whate...