Adapts the decoder from PR #3561 by Steven Bontius, who reverse
engineered the protocol (documented at
https://github.com/StevenBontius/watts-wfht-ha/blob/main/docs/WATTS_WFHT_RF_PROTOCOL.md)
for a newer, LCD-display generation of Watts underfloor heating
thermostat -- unrelated to the existing watts_thermostat.c decoder,
which targets an older ADEV-based generation with a completely
different protocol (PWM vs. this one's Manchester, different frame
layout, no CRC-16).
Verified against:
- The 2 worked examples in the protocol doc (independently recomputed
both CRC-8 and CRC-16/CMS in Python against the documented
parameters; both check out).
- All 3 real captures from the companion rtl_433_tests#502 PR (pairing,
on, off) -- decode correctly, including the ~2 Hz pairing cadence,
the A-B-A setpoint jitter around a real transition, and the 0.0 C
setpoint on the "off" capture.
Full local regression suite: no new false positives.
c9dcd8090f