OnlineJudgeBo/onlinejudgebo-admin-api ? reverse-engineered prompt

Build me the backend for an online judge admin system in .NET 8 with ASP.NET Core. I want it organized with clean Onion style, so the business logic stays in the center and the API, database, file storage, and other external integrations stay outside. It should support things like problems, contests, users, roles, submissions, rankings, academic data, schedules, and a public API for login and basic site data.

Use MariaDB with Entity Framework Core, JWT login, Swagger while developing, and make it easy to run with Docker. Please keep controllers thin, put the real work in application services, and use interfaces so the core logic does not depend on database or web details. Also include the pieces for local files, S3 style storage, and the IDE integration mentioned in the project. If anything is unclear, check the current docs online or keep the implementation consistent with the existing structure.