Rolling the mouse wheel over the hundreds / tens / units-of-kHz digit of the
header (and compact top-bar) frequency steps the frequency by 100 / 10 / 1 kHz
(wheel up = higher). The display updates optimistically on every notch and the
rig QSYs over CAT, debounced so a fast scroll doesn't flood the link. Only the
kHz digits are wheel-sensitive; MHz and Hz stay static.
New FreqWheelDisplay component (replaces the plain fmtFreqDots span in both the
full header and the compact top bar) + nudgeFreqHz handler.
rouggy
e5ff30823d