dedetive/misle-java ? reverse-engineered prompt

Build me a playable Java game from this repo, a top down 2D tactical RPG with turn based combat and some real time exploration if that is already part of the project. I want it to launch cleanly, have a simple main menu, a basic game loop, movement, combat turns, and enough of the world and room systems to feel like a real game instead of a demo. Please keep it working with JDK 21 or newer, and make sure the build scripts still produce a jar I can run easily on Windows and Linux.

If some parts are already there, improve and connect them instead of starting over. Keep the original lore friendly structure in mind, but focus first on making the gameplay solid and easy to test. Also check the docs for controls, settings, items, and rooms, and use those as the source of truth. If you need to verify anything current, look up the latest docs online first.