Add --udp-tee / RUVIEW_UDP_TEE: every datagram the source allowlist admits
is copied unchanged to up to four loopback targets, so a fusion host or
Cognitum cog can read full I/Q, sequence numbers and sync packets without
binding the CSI port. Targets must be loopback and may not reuse the
listener port or port 0. Sends are non-blocking and drops are counted. Off
by default.
Tests: cargo test -p wifi-densepose-sensing-server --no-default-features
--lib udp_tee (6 passed) and --bin sensing-server (332 passed). Loopback
smoke test of the debug binary: a 288-byte datagram sent to the UDP port
arrived byte for byte at the tee target, and a non-loopback --udp-tee
target made the server exit 1 with "must be a loopback address".
Co-Authored-By: claude-flow <ruv@ruv.net>