GroundZero Boss Models

Drop-in layout:
models/<model_id>/<model>.bbmodel
models/<model_id>/<texture>.png

Default animation mode is vanilla_zombie. This ignores Blockbench animation tracks and drives common bones (head/body/arm0/arm1/leg0/leg1) with normal Minecraft zombie movement.
Optional models/<model_id>/bossmodel.json:
{"animation_mode":"bbmodel"}
Use that only when you want the custom Blockbench animations instead.

The texture may also be embedded in the .bbmodel.
Use /gzboss reload after changing files.
Use /gzboss testspawn <model_id> to test.
