Washer (#6): instantaneousPower is a dead sentinel ('-500') on every
TP1-class washer dump collected so far, and cumulativePower is absent
outright on at least one model. WASHER_ENERGY_METER now hides both
sensors instead of showing a misleading "0 W"/perpetual "unavailable".
Fridge (#7): temperature sensors/setpoints hardcoded '°F', ignoring the
unit each device actually reports per-reading -- fixed via a new
unit_fn hook read live from the resource. Also corrects
DEFROST_BLOCK_STATUS's polarity (DEFROST_BLOCK_ON means actively
defrosting, not "blocked", confirmed against live dumps) and adds
REFRIGERATION_FALLBACK for /refrigeration/0, closing the last unbound
href surfaced by issue #7's diagnostic dump.
Oven: applies the same live-unit-reading fix defensively to
OVEN_SETPOINT, which shares the same aggregate resource shape.