- Move useElementSize ref to wrapper div so HoverCard.Target's ref
merging doesn't break element measurement (dots were hidden because
height returned 0, triggering isTooSmallForIndicators)
- Add pos='relative' to Container so NotificationIndicator anchors
to the day cell
- Add openDelay/closeDelay directly to each HoverCard as fallback in
case HoverCard.Group context doesn't propagate through Mantine
Calendar's internal rendering