- Bump Gradle to 8.5 and adjust related configs.
- Upgrade from JDK 17 to JDK 21.
- Replace deprecated methods with modern equivalents (`withDisplayName` -> `withCustomName`).
- Refactor and simplify event handling (e.g., PlayerLoginEvent -> AsyncPlayerConfigurationEvent).
- Fix minor issues with player and inventory handling.
- Improve Gradle startup scripts for better compatibility.
- Transition plugin handling from deprecated to current class references.
- General cleanup and code modernization.