Shared demo business code: fully annotated entities, passthrough settings, callbacks and REST endpoints (compiled against the Boot 3.5.16 baseline; both launcher shells reuse the same bytecode).

Boot 3.5.16 demo launcher shell: only the application class and configuration; all business code is reused from example-common.

Boot 4.0.3 demo launcher shell: only the application class and configuration; all business code is reused from example-common (the same bytecode running on the other Boot generation).