sb7_pack / sb7_field are the one pack and unpack of the stream kinds' record (56 bits, least significant
first: x 12, z 12, y 12 over the chunk's y span, scale 6, yaw 6, seed 4, wind 4, read as a low and a high
word), which the bake and the game both import; stream_emit_baked decodes a prefix of it.
layer_chunks_begin / layer_chunk_put / layer_chunk_drop keep a fixed layer (trees, boulders, stones:
12-byte records) as a slab per resident chunk in its instance list, an n x n index made at load, the
list re-uploaded at most once a frame. Nothing calls them yet: behaviour unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
