Improves event overlap detection

Refactors event overlap detection to use pixel-based comparison.
This improves accuracy and addresses issues with incorrect overlap
calculations when events have slight time differences but visually overlap.
It removes dependency on the event manager and the need to convert elements
to calendar events for overlap detection.

src/managers/EventOverlapManager.ts

@@ -25,6 +25,7 @@ export class EventOverlapManager {
   private static readonly STACKING_WIDTH_REDUCTION_PX = 15;
   private nextZIndex = 100;
 
+
   /**
    * Detect overlap mellem events baseret på faktisk time overlap og start tid forskel
    */
@@ -200,6 +201,7 @@ export class EventOverlapManager {
     eventElement.style.zIndex = '';
   }
 
+
   /**
    * Beregn position for event gruppe
    */