cync_lan (Home Assistant custom_component) v2.13.0

Colour temperature never worked. It does now.

Cync devices speak a 0-100 scale on the wire, whatever the bulb's real kelvin
range is. This integration passed Home Assistant's kelvin value straight to
the device, and the library refuses anything above 100 - so every colour
temperature you set was rejected with "Invalid temperature! must be 0-100"
and no packet was ever sent. Moving the slider did nothing, silently, unless
you were reading the debug log.

Reading was wrong in the same way: the raw 0-100 came back as if it were
kelvin, so a bulb sitting at mid-white reported something like "50 K" -
far below the minimum this integration itself advertises.

Both directions convert now. The MQTT add-on has always done this with its
own kelvin2cync/cync2kelvin; the conversion now lives in the library so
there is one implementation rather than one-and-a-missing-one.

Two smaller things came with it:

• The advertised range and the conversion range now come from the same
  place. A device declaring no maximum kept Home Assistant's default of
  6535 K while the conversion scaled against 7000, so the top of the slider
  mapped to 90 rather than 100.
• The device's 254 "in RGB mode" marker is no longer reported as a colour
  temperature while a bulb is showing colour.

How it survived: the test asserted set_temperature(4000) - the exact
pass-through that fails - and another was named
test_color_temp_kelvin_reads_through_when_supported, pinning the read side
just as literally. Both now check that whatever reaches the wire is inside
the range the wire accepts, across the whole span the entity advertises
rather than at one point.

Requires cync-lan 0.13.0.