🚑 Hotfix: the schedule sensor was never created
The sensor's provider filter used a literal that doesn't match the actual Xenio provider constant, so it was silently skipped (the switch had the mirror-image bug and would have appeared on Fenix too). Both now read the provider from the config entry.
The schedule entities are also renamed to Device schedule / Geräte-Zeitplan — the old name collided with the existing smart-preheat sensor in several languages, and the new one makes clear the plan lives in the heater.
Writing was verified working on a CX110 in this release cycle: set_schedule produced exactly the expected bytes.