spring-petclinic/spring-petclinic-rest — reverse-engineered prompt

Build me a simple backend only pet clinic app in Java that exposes a REST API, with no website or admin screens. I want it to manage pet owners, pets, vets, visits, pet types, specialties, and basic user creation. Please include the usual create, read, update, and delete routes for those records, plus the nested owner and pet actions like adding a pet to an owner and adding a visit for a pet.

Make it easy to run locally on port 9966 with sample data loaded by default, and give me API docs in Swagger plus a health check endpoint. Use an in memory database as the default so it works right away, but keep it easy to switch to MySQL or Postgres later, ideally with Docker support too. Please wire up sensible validation, clean JSON responses, and anything needed so I can test the endpoints quickly.

If there are existing conventions for this pet clinic sample, follow them, and look up current docs online if you need to.