The overlay peer report carried packet counts only, so the GUI could show
packets/s but no byte throughput. Adds tx_bytes/rx_bytes to OverlayPeerReport
and fills them from each data plane:
- the wg and wg-quic plugins already counted plaintext bytes per peer; the CLI
now maps them into the report;
- the generic tunnel (tcp-tls) gains tx_bytes/rx_bytes on its peer state and
report, incremented by the plaintext length at the same points it counts
packets.
The local control protocol version is bumped (TSN 15 -> 16) since the report
shape changed; a client and agent on different builds already detect and report
the mismatch.
Checks: fmt, clippy --workspace --all-targets -D warnings, and the tsunagi lib,
tsunagi-cli and wg-quic local_control tests pass on macOS.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>