da578/dzuls-dev-studio-api ? reverse-engineered prompt

Build me a backend API for a freelance software studio that can manage client work from start to finish.

It should let me track feature requests and backlogs, handle client payments safely with idempotency so I never charge someone twice, and send automated email notifications when things change. I also need login, roles, and permission checks so only the right people can see or change certain data. Please make it solid and production ready, with clear validation, good error responses, and safe database transactions.

Use the stack that fits this repo, and keep it type safe. If anything is missing, look up the current docs online and fill in the gaps. I’d like the API to be easy to test, include OpenAPI docs, and be organized in a clean way so it’s simple to extend later with more studio features.