mir-backend-jvm-spring

Make It Right (Spring Boot module). Spring Boot + Spring Data JPA/Hibernate + Spring Security + Spring MVC/WebFlux reliability footguns specific to this framework stack. Covers: @Transactional self-invocation (same-bean call bypasses the proxy → no transaction), checked exceptions not rolling back by default, propagation/isolation pitfalls, JPA/Hibernate N+1 with lazy associations, LazyInitializationException outside the session, OPEN_IN_VIEW antipattern, singleton bean scope storing per-request state, @Async needing an explicit thread pool and swallowing exceptions, @Valid + DTOs against overposting, and Spring Security method-level authorization for object-level checks. Always loads TOGETHER WITH mir-backend (the gates) and mir-backend-jvm (JVM runtime concerns: thread pools, virtual threads, GC, container heap, cold start, JMM visibility, ThreadLocal hygiene); this module only adds Spring Boot / Spring Data library mechanics. TRIGGER only when the JVM backend stack is Spring Boot — building, reviewing, or debugging a controller, service, @Transactional method, JPA entity, Spring Security config, or @Async task. SKIP for Quarkus, Micronaut, Vert.x, or any non-Spring JVM framework (those get their own mir-backend-jvm-<framework> module), and for non-JVM runtimes.