Updates drag-and-drop overlap handling

Replaces the old overlap handling system with a new approach.

The new system recalculates overlaps after a drag-and-drop action and re-renders the affected events, avoiding manual group management. This simplifies the overlap resolution logic and improves performance.

src/renderers/EventRenderer.ts

@@ -5,7 +5,6 @@ import { calendarConfig } from '../core/CalendarConfig';
 import { DateCalculator } from '../utils/DateCalculator';
 import { eventBus } from '../core/EventBus';
 import { CoreEvents } from '../constants/CoreEvents';
-//import { SimpleEventOverlapManager, OverlapType } from '../managers/SimpleEventOverlapManager';
 import { OverlapDetector, OverlapResult, EventId } from '../utils/OverlapDetector';
 
 /**
@@ -305,11 +304,7 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
     console.log('handleDragStart:', eventId);
     this.originalEvent = originalElement;
     
-    // Remove stacking styling during drag
+    // Remove stacking styling during drag will be handled by new system
-    // TODO: Replace with new system
-    // if (this.overlapManager.isStackedEvent(originalElement)) {
-    //   this.overlapManager.removeStackedStyling(originalElement);
-    // }
     
     // Create clone
     this.draggedClone = this.createEventClone(originalElement);
@@ -396,9 +391,7 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
     
     
     // Detect overlaps with other events in the target column and reposition if needed
-    //this.detectAndHandleOverlaps(this.draggedClone, finalColumn);
+    this.handleDragDropOverlaps(this.draggedClone, finalColumn);
-    // TODO: Implement new drag overlap handling
-    //this.new_handleEventOverlaps(columnEvents, eventsLayer);
     // Clean up
     this.draggedClone = null;
     this.originalEvent = null;
@@ -471,12 +464,75 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
     }, 100);
   }
   
+  /**
+   * Handle overlap detection and re-rendering after drag-drop
+   */
+  private handleDragDropOverlaps(droppedElement: HTMLElement, targetColumn: string): void {
+    const targetColumnElement = document.querySelector(`swp-day-column[data-date="${targetColumn}"]`);
+    if (!targetColumnElement) return;
+    
+    const eventsLayer = targetColumnElement.querySelector('swp-events-layer') as HTMLElement;
+    if (!eventsLayer) return;
+    
+    // Convert dropped element to CalendarEvent with new position
+    const droppedEvent = this.elementToCalendarEventWithNewPosition(droppedElement, targetColumn);
+    if (!droppedEvent) return;
+    
+    // Get existing events in the column (excluding the dropped element)
+    const existingEvents = this.getEventsInColumn(eventsLayer, droppedElement.dataset.eventId);
+    
+    // Find overlaps with the dropped event
+    const overlappingEvents = this.overlapDetector.resolveOverlap(droppedEvent, existingEvents);
+    
+    if (overlappingEvents.length > 0) {
+      // Remove only affected events from DOM
+      const affectedEventIds = [droppedEvent.id, ...overlappingEvents.map(e => e.id)];
+      eventsLayer.querySelectorAll('swp-event').forEach(el => {
+        const eventId = (el as HTMLElement).dataset.eventId;
+        if (eventId && affectedEventIds.includes(eventId)) {
+          el.remove();
+        }
+      });
+      
+      // Re-render affected events with overlap handling
+      const affectedEvents = [droppedEvent, ...overlappingEvents];
+      this.new_handleEventOverlaps(affectedEvents, eventsLayer);
+    }
+    // If no overlaps, the dropped element stays as is
+  }
+
+  /**
+   * Get all events in a column as CalendarEvent objects
+   */
+  private getEventsInColumn(eventsLayer: HTMLElement, excludeEventId?: string): CalendarEvent[] {
+    const eventElements = eventsLayer.querySelectorAll('swp-event');
+    const events: CalendarEvent[] = [];
+    
+    eventElements.forEach(el => {
+      const element = el as HTMLElement;
+      const eventId = element.dataset.eventId;
+      
+      // Skip the excluded event (e.g., the dropped event)
+      if (excludeEventId && eventId === excludeEventId) {
+        return;
+      }
+      
+      const event = this.elementToCalendarEvent(element);
+      if (event) {
+        events.push(event);
+      }
+    });
+    
+    return events;
+  }
+
   /**
    * Remove event from any existing groups and cleanup empty containers
-   * TODO: Replace with new system
+   * In the new system, this is handled automatically by re-rendering overlaps
    */
   private removeEventFromExistingGroups(eventElement: HTMLElement): void {
-    // TODO: Implement with new system
+    // With the new system, overlap relationships are recalculated on drop
+    // No need to manually track and remove from groups
   }
   
   /**