Track ESP-NOW slaves in a shared registry and respond to CLIENT_INFO
with protobuf ClientInfoResponse; ESP-NOW path upserts registry entries.
Co-authored-by: Cursor <cursoragent@cursor.com>
Slave responds and logs only on first discover from a given master MAC;
subsequent broadcasts on the same network are silently ignored.
Co-authored-by: Cursor <cursoragent@cursor.com>