feat(sensor): add missing Kesselzustand status codes 89 & 90 (v0.3.5)
Status values 89 and 90 were missing from KESSELZUSTAND_MAPPING,
causing Home Assistant to display "Unknown (89)" and "Unknown (90)"
after the Scheitholz heating cycle. Added:
89: "Abstellen Warten (SH)"
90: "Abreinigen (SH)"