rememberAnimatedDayValues
fun rememberAnimatedDayValues(values: Map<LocalDate, Float>, animationSpec: AnimationSpec<Float> = tween(durationMillis = 300)): (LocalDate) -> Float?
Animates per-day values toward their targets and returns a lookup for data-driven decorators (progressRing, progressBar, heatmap). New dates animate from 0; changed dates ease to the new target; removed dates disappear immediately. The lookup reads snapshot state, so decorators redraw automatically while animating.