Refactors header drag interaction to eliminate ghost columns

Updates the `HeaderManager` to utilize `mouseenter` and `mouseleave` events on the calendar header for improved performance and accuracy.
Calculates the target date based on the mouse's X-coordinate within the header.

Removes the need for 'ghost columns' by simplifying the logic. This significantly reduces complexity.
The `AllDayEventRenderer` is modified to reflect this change, omitting ghost column creation.

Updates `DragDropManager` to accommodate the new interaction model.
Various console logs are added for debugging purposes.

src/managers/DragDropManager.ts

@@ -96,18 +96,36 @@ export class DragDropManager {
     this.eventBus.on('header:mouseover', (event) => {
       const { targetDate, headerRenderer } = (event as CustomEvent).detail;
       
+      console.log('🎯 DragDropManager: Received header:mouseover', {
+        targetDate,
+        draggedEventId: this.draggedEventId,
+        isDragging: !!this.draggedEventId
+      });
+      
       if (this.draggedEventId && targetDate) {
         // Find dragget element dynamisk
         const draggedElement = document.querySelector(`swp-event[data-event-id="${this.draggedEventId}"]`);
         
+        console.log('🔍 DragDropManager: Looking for dragged element', {
+          eventId: this.draggedEventId,
+          found: !!draggedElement,
+          tagName: draggedElement?.tagName
+        });
+        
         if (draggedElement) {
+          console.log('✅ DragDropManager: Converting to all-day for date:', targetDate);
+          
           // Element findes stadig som day-event, så konverter
           this.eventBus.emit('drag:convert-to-allday', {
             targetDate,
             originalElement: draggedElement,
             headerRenderer
           });
+        } else {
+          console.log('❌ DragDropManager: Dragged element not found');
         }
+      } else {
+        console.log('⏭️ DragDropManager: Skipping conversion - no drag or no target date');
       }
     });