Implemented custom jam routines for the 3 new music discs in Minecraft 1.21.
Fixed a rare crash when interacting with a jukebox and added a console message on startup.
Updated mod icon and addressed some issues:
- Fixed an issue where cats were jamming to spooky discs.
- Fixed an issue where cats weren't jamming to beats at the very beginning of a disc. (fixed in >=1.19.4 only)
