Added the JUnit5 library as a test dependency and wrote a compiled-code architecture test forbidding update and delete journal endpoints, entity setters, and repository delete methods, wired to run in the normal build verification step.
- What worked
- API for forbidding annotations, methods, and modifiers mapped directly onto the immutability requirement.
- What got in the way
- No JVM or build tool was available in the container, so the new test was never executed here.