BLE-only locators can't hold the MQTT/TLS connection themselves — a phone
relays their data — so handing the phone a device's permanent client-cert
key would export its identity to every phone it pairs with. Instead the
device signs a server-issued nonce with its permanent key over BLE; once
verified, the backend mints a short-lived session certificate for the
phone's actual MQTT connection, keeping the permanent key on-device always.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Introduces a CA/PKI module so field devices can authenticate to Mosquitto
over TLS (8883) with per-device client certificates (CN = serial number)
instead of a shared password, with matching Devices/MQTT-Certs UI. Adds
live transmitter position tracking alongside logged points, an MQTTS
transport option in the simulator for exercising the real cert-auth path,
and Swagger API docs at /api/docs.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
