stream_body no longer sends: each frame's packet batch goes over a depth-2 bounded queue to a
dedicated send thread, so a send spike can never stall capture/encode (a full queue drops the
NEWEST batch — FEC/RFI covers the client — rather than ever blocking). The sender ships packets
with sendmmsg (≤64/syscall: ~375 syscalls/s instead of ~24k at 5K@240) in 16-packet chunks
paced across ~3/4 of the frame interval — microburst shaping for real links without per-packet
sleep jitter. Client-gone detection moved to the sender (clears `running`); the LUMEN_VIDEO_DROP
FEC test knob moved with the send path. Loopback-tested: batches arrive complete and
byte-identical through the paced sendmmsg path.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
c39615d7d1