Sens'it Discovery v3 byte 1 layout per official spec:
bits 7-3: mode
bit 2 : special / button alert
bits 1-0: MSB (2 bits) of sensor data
Previous decoder had button on bit 0 and used only bit 2 as data MSB
(9-bit values). Real payloads confirmed 10-bit: e.g. b609a861 was
decoded as -4°C but correctly resolves to 28°C with the fixed layout.
Fixes applied consistently to all v3 modes:
- Temperature: 10-bit temp with formula (raw - 200) / 8
- Light: 10-bit brightness with formula raw / 96
- Door/Vibration/Magnet: 2-bit status from bits 1-0
Existing DB entries re-decoded in place.