Refactors calendar event rendering and management

Improves code organization and maintainability by separating concerns related to all-day event rendering, header management, and event resizing.

Moves all-day event rendering logic into a dedicated `AllDayEventRenderer` class, utilizing the factory pattern for event element creation.

Refactors `AllDayManager` to handle all-day row height animations, separated from `HeaderManager`.

Removes the `ResizeManager` and related functionality.

These changes aim to reduce code duplication, improve testability, and enhance the overall architecture of the calendar component.

wwwroot/css/calendar-layout-css.css

@@ -461,7 +461,7 @@ swp-events-layer {
   pointer-events: none; /* Allow clicks to pass through to day column */
 }
 
-swp-event {
+swp-day-columns swp-event {
   pointer-events: auto;
 }