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/AllDayManager.ts

@@ -30,13 +30,27 @@ export class AllDayManager {
   private setupEventListeners(): void {
     eventBus.on('drag:convert-to-allday', (event) => {
       const { targetDate, originalElement } = (event as CustomEvent).detail;
+      console.log('🔄 AllDayManager: Received drag:convert-to-allday', {
+        targetDate,
+        originalElementId: originalElement?.dataset?.eventId,
+        originalElementTag: originalElement?.tagName
+      });
       this.handleConvertToAllDay(targetDate, originalElement);
     });
     
     eventBus.on('drag:convert-from-allday', (event) => {
       const { draggedEventId } = (event as CustomEvent).detail;
+      console.log('🔄 AllDayManager: Received drag:convert-from-allday', {
+        draggedEventId
+      });
       this.handleConvertFromAllDay(draggedEventId);
     });
+
+    // Listen for requests to ensure all-day container exists
+    eventBus.on('allday:ensure-container', () => {
+      console.log('🏗️ AllDayManager: Received request to ensure all-day container exists');
+      this.ensureAllDayContainer();
+    });
   }
 
   /**
@@ -325,6 +339,41 @@ export class AllDayManager {
     this.checkAndAnimateAllDayHeight();
   }
 
+  /**
+   * Ensure all-day container exists, create if needed
+   */
+  public ensureAllDayContainer(): HTMLElement | null {
+    console.log('🔍 AllDayManager: Checking if all-day container exists...');
+    
+    // Try to get existing container first
+    let container = this.getAllDayContainer();
+    
+    if (!container) {
+      console.log('🏗️ AllDayManager: Container not found, creating via AllDayEventRenderer...');
+      
+      // Use the renderer to create container (which will call getContainer internally)
+      this.allDayEventRenderer.clearCache(); // Clear cache to force re-check
+      
+      // The renderer's getContainer method will create the container if it doesn't exist
+      // We can trigger this by trying to get the container
+      const header = this.getCalendarHeader();
+      if (header) {
+        container = document.createElement('swp-allday-container');
+        header.appendChild(container);
+        console.log('✅ AllDayManager: Created all-day container');
+        
+        // Update our cache
+        this.cachedAllDayContainer = container;
+      } else {
+        console.log('❌ AllDayManager: No calendar header found, cannot create container');
+      }
+    } else {
+      console.log('✅ AllDayManager: All-day container already exists');
+    }
+    
+    return container;
+  }
+
   /**
    * Clean up cached elements and resources
    */