recolour pipeline: return a CSS colour (e.g.
var(--color-…)) for a given MuscleKey, or undefined to keep the
neutral default. Omit entirely for the plain, uncoloured map.
Returns Element
Remarks
The native context menu is suppressed across the whole map, with or
without interaction handlers — an accidental Back from it costs the user
whatever they had staged, and an inline SVG offers nothing useful there.
A front + back anatomical muscle map. Presentational by default; opt-in pointer interaction via
onMuscleHover/onMuscleClick(+highlightedKey).