GroundZero Resource Pack v45.1

Zombie Nest spawn scream:
- Original audio was valid OGG/Vorbis but mastered very quietly.
- Audio has been loudness-normalized for reliable in-game playback.
- Sound event remains: groundzero:zombienest.spawn
- File remains: assets/groundzero/sounds/nests/zombie_nest_spawn.ogg

The Zombie Nest Core model/texture paths are unchanged.
