Enhances event layout engine with advanced rendering logic

Introduces sophisticated event layout algorithm for handling complex scheduling scenarios

Adds support for:
- Grid and stacked event rendering
- Automatic column allocation
- Nested event stacking
- Threshold-based event grouping

Improves visual representation of overlapping and concurrent events

src/v2/managers/DragDropManager.ts

@@ -25,6 +25,8 @@ interface DragState {
   targetY: number;
   currentY: number;
   animationId: number;
+  sourceDateKey: string;        // Source column date (where drag started)
+  sourceResourceId?: string;    // Source column resource (where drag started)
 }
 
 /**
@@ -144,7 +146,7 @@ export class DragDropManager {
     // Remove ghost
     this.dragState.ghostElement.remove();
 
-    // Get column data
+    // Get column data (target = current column, source = where drag started)
     const dateKey = this.dragState.columnElement.dataset.date || '';
     const resourceId = this.dragState.columnElement.dataset.resourceId;
 
@@ -155,7 +157,9 @@ export class DragDropManager {
       snappedY,
       columnElement: this.dragState.columnElement,
       dateKey,
-      resourceId
+      resourceId,
+      sourceDateKey: this.dragState.sourceDateKey,
+      sourceResourceId: this.dragState.sourceResourceId
     };
 
     this.eventBus.emit(CoreEvents.EVENT_DRAG_END, payload);
@@ -200,7 +204,9 @@ export class DragDropManager {
       currentColumn: columnElement,
       targetY: Math.max(0, targetY),
       currentY: startY,
-      animationId: 0
+      animationId: 0,
+      sourceDateKey: columnElement.dataset.date || '',
+      sourceResourceId: columnElement.dataset.resourceId
     };
 
     // Emit drag:start