Extends the existing MapEnhancer gear menu integration with a full settings
panel covering the options added by the community fork: marker visibility
toggles, scale sliders for flares, junctions, track lines, and crossings,
and bulk switch reset buttons.
Also adds pan-cancels-follow and right-click to recenter on player toggles,
three independent opacity controls (Window, Map Elements, Map Background),
a per-element hover minimum of 50% for the window chrome so controls stay
reachable at low opacity, and fixes to make the compass and toolbar correctly
respond to their respective sliders. Both surfaces (in-game overlay and OS
popout) maintain parity on all new settings.