Ackfield MQTT config kit (ship with customer install)

Copy this tree to the office PC, for example:
  C:\mqtt\config\  ← contents of config\
  C:\mqtt\data\    ← empty folder (Mosquitto fills on first run)

Or run from ackfield-receive:
  npm run mqtt:init
  (uses MQTT_CONFIG_DIR from .env.docker or C:\mqtt by default)

After Mosquitto is running, open Ackfield-Receive → Users to add phone MQTT users.
