Improves all-day event drag and drop

Enhances the drag and drop experience for all-day events by expanding the header to display the all-day row when dragging an event over it.

Introduces constants for all-day event layout.

src/managers/ColumnDetector.ts

@@ -2,6 +2,9 @@
  * ColumnDetector - Bare detect hvilken kolonne musen er over
  */
 
+import { ALL_DAY_CONSTANTS } from '../core/CalendarConfig';
+import { eventBus } from '../core/EventBus';
+
 export class ColumnDetector {
   private currentColumn: string | null = null;
   private isMouseDown = false;
@@ -67,8 +70,18 @@ export class ColumnDetector {
     // Lyt til mouse down og up
     document.body.addEventListener('mousedown', this.handleMouseDown.bind(this));
     document.body.addEventListener('mouseup', this.handleMouseUp.bind(this));
+    
+    // Listen for header mouseover events
+    eventBus.on('header:mouseover', (event) => {
+      const { dayHeader, headerRenderer } = (event as CustomEvent).detail;
+      if (this.isMouseDown && this.draggedClone) {
+        console.log('Dragging clone over header - calling addToAllDay');
+        headerRenderer.addToAllDay(dayHeader);
+      }
+    });
   }
 
+
   private handleMouseMove(event: MouseEvent): void {
     // Hvis musen er holdt nede, tjek for snap interval vertikal bevægelse
     if (this.isMouseDown) {
@@ -280,6 +293,19 @@ export class ColumnDetector {
     }
   }
 
+  /**
+   * Expand header to show all-day row when clone is dragged into header
+   */
+  private expandHeaderForAllDay(): void {
+    const root = document.documentElement;
+    const currentHeight = parseInt(getComputedStyle(root).getPropertyValue('--all-day-row-height') || '0');
+    
+    if (currentHeight === 0) {
+      root.style.setProperty('--all-day-row-height', `${ALL_DAY_CONSTANTS.SINGLE_ROW_HEIGHT}px`);
+      console.log('Header expanded for all-day row');
+    }
+  }
+
   public destroy(): void {
     document.body.removeEventListener('mousemove', this.handleMouseMove.bind(this));
     document.body.removeEventListener('click', this.handleClick.bind(this));