docs/Architecture-signed-its.drawio (with a PNG export beside it, like
Architecture2): PKI (today's demo chain, and dashed the future EU C-ITS path
with the lab's registered root), the phone app's transmit and receive path,
the USB-C and BLE links with their heartbeats, the ESP32-C5 firmware (link
endpoints, session, signing through vanetza-idf with the key in NVS, the
unsigned geonet.c path, radio and raw receive), the ITS-G5 air and the bench
receivers (V2X2MAP with signature check, CiT One, RSU, sim car), and a legend
of the station-link messages and recovery behaviour.
