RHI Metro MQTT broker

Host: broker-metro.smartsaving.com.br
Port: 1885 (MQTT)
Topic: rhi/ana-rosa/readings

Payload JSON:
  {"tag":"RHI-1A-01","value":2.35,"ts":"2026-09-18T17:00:00Z"}

IMPORTANT: ts must always be UTC (ISO-8601 ending in Z).
Do not send local/Brazil timezone — convert to UTC on the device.

MQTTX: mqtt://broker-metro.smartsaving.com.br:1885