Build tube geometry for one chunk. Reads ONLY chunk.positions (self-contained, no IR) so a chunk
can be handed to a worker as a single transferable buffer (RR-008 §4.1) — output is byte-identical to
the previous IR-indexed implementation, since chunk.positions carries the same endpoints.
Build tube geometry for one chunk. Reads ONLY
chunk.positions(self-contained, no IR) so a chunk can be handed to a worker as a single transferable buffer (RR-008 §4.1) — output is byte-identical to the previous IR-indexed implementation, sincechunk.positionscarries the same endpoints.