Moves event hover handling from DragDropManager to a new DragHoverManager.
This improves separation of concerns and makes the hover logic more modular and reusable. The DragHoverManager is now responsible for tracking when the mouse hovers over events, and it emits events for other parts of the application to react to.
The drag:start event is used to deactivate hover tracking when a drag operation starts.
Adds edge scrolling to automatically scroll the calendar
when dragging an event near the edges of the view.
This improves the drag-and-drop experience by allowing users
to move events beyond the visible area.
Removes auto-scroll logic from the event renderer, centralizing
the scrolling behavior within the new edge scroll manager.
Adds a resize handle manager to handle mouse hover
effects on calendar events and display a resize indicator.
This allows users to visually identify and initiate
event resizing by hovering near the bottom edge of an event.
