Improves header drag-and-drop event handling

Enhances drag leave logic for more precise event tracking
- Adds conditional cleanup for grid-to-header drag events
- Updates drag state management during column transitions
- Prevents premature ghost element removal

src/v2/features/headerdrawer/HeaderDrawerRenderer.ts

@@ -285,11 +285,16 @@ export class HeaderDrawerRenderer {
   }
 
   /**
-   * Handle drag leaving header - remove preview and restore source
+   * Handle drag leaving header - cleanup for grid→header drag only
    */
-  private handleDragLeave(_payload: IDragLeaveHeaderPayload): void {
+  private handleDragLeave(payload: IDragLeaveHeaderPayload): void {
+    // Only cleanup for grid→header drag (when grid event leaves header back to grid)
+    // For header→grid drag, the header item stays as ghost until drop
+    if (payload.source === 'grid') {
       this.cleanup();
     }
+    // For header source, do nothing - ghost stays until EVENT_DRAG_END
+  }
 
   /**
    * Handle drag end - finalize based on drop target

src/v2/managers/DragDropManager.ts

@@ -441,6 +441,22 @@ export class DragDropManager {
         };
 
         this.eventBus.emit(CoreEvents.EVENT_DRAG_LEAVE_HEADER, payload);
+
+        // Re-attach to the new swp-event created by EventRenderer
+        if (targetColumn) {
+          const newElement = targetColumn.querySelector(
+            `swp-event[data-event-id="${this.dragState.eventId}"]`
+          ) as HTMLElement;
+
+          if (newElement) {
+            this.dragState.element = newElement;
+            this.dragState.columnElement = targetColumn;
+            this.dragState.currentColumn = targetColumn;
+
+            // Start animation for the new element
+            this.animateDrag();
+          }
+        }
       } else {
         // Grid event leaving header → restore to grid
         const payload: IDragLeaveHeaderPayload = {