Strip @JvmField/@JvmStatic annotations (pure Kotlin cleanup)
Remove 1145 unnecessary @JvmField/@JvmStatic annotations now
that no Java code exists. Only @JvmStatic on main() is kept
for JAR manifest entry point.
@JvmField retained on GameShell.width/height to avoid
Canvas.getWidth/getHeight signature clash.
Replace SoundPlayer.setVolume()/getVolume() explicit functions
with Kotlin property access (SoundPlayer.volume = x).