Move the record ring, wake semaphore, and both pool arenas/free rings into
GSBackQueue::Channel. Each GSState owns channel storage and works through a
m_chan pointer (defaulting to its own storage), so the upcoming two-object
pipelined split can aim a front parser object at the back object's channel
without touching any record or pool logic. DrainBackQueue keys on the
channel's consumer_running flag instead of the producer flag, making drains
work from either side; payload node-0 adoption becomes an explicit
AdoptTransferBuffer() run by the staging object. The destructor frees only
its own channel storage. No behavior change in any mode.
Co-Authored-By: Claude <noreply@anthropic.com>
Brian DegenhardtandClaude
94de4fd55c