a compact WiFi <-> OpenTherm (master & slave) interface

https://www.seegel-systeme.de/2025/01/05/ot-thing-das-universelle-wifi-opentherm-interface/

https://community.home-assistant.io/t/ot-thing-an-opentherm-wifi-gateway-with-integrated-ot-master-slave/824667

When reporting issues please supply:

• Brand & model of boiler & roomunit
• Log
• status JSON (http://[OTTHING-IP]/status)
• configuration JSON (http://[OTTHING-IP]/config)
• OT status JSON (http://[OTTHING-IP]/otitems)