ityouknow/spring-boot-examples ? reverse-engineered prompt

Build me a simple Spring Boot learning examples project, like a collection of small demo apps that show the basics in the clearest way possible. I want one repo with separate examples for things like a hello world page, custom startup banner, scheduled tasks, file upload, web controllers, Thymeleaf pages, JPA CRUD, MyBatis CRUD, MongoDB, Redis, RabbitMQ, email sending, and Docker plus Docker Compose with MySQL and Nginx.

Keep each example small, easy to run, and focused on one thing so it’s good for beginners. Please make the demos feel practical, with a few test cases where it makes sense, and simple instructions in the README so someone can open a module and get it running quickly. Use the current Spring Boot 3 style, and look up current docs online if you need to.