Improves drag and drop functionality

Enhances drag and drop behavior by introducing free positioning during auto-scroll and snapping to grid intervals.

- Introduces a `calculateFreePosition` method to allow events to follow the mouse exactly during auto-scroll.
- Modifies the drag move event to emit the snapped position during normal drag behavior.
- Updates event rendering to use grid settings for snap intervals.
- Updates grid styles to configure CSS variables dynamically.

src/managers/GridManager.ts

@@ -8,6 +8,7 @@ import { calendarConfig } from '../core/CalendarConfig';
 import { CoreEvents } from '../constants/CoreEvents';
 import { ResourceCalendarData, CalendarView } from '../types/CalendarTypes';
 import { GridRenderer } from '../renderers/GridRenderer';
+import { GridStyleManager } from '../renderers/GridStyleManager';
 import { DateCalculator } from '../utils/DateCalculator';
 
 /**
@@ -19,11 +20,13 @@ export class GridManager {
   private resourceData: ResourceCalendarData | null = null;
   private currentView: CalendarView = 'week';
   private gridRenderer: GridRenderer;
+  private styleManager: GridStyleManager;
   private eventCleanup: (() => void)[] = [];
   
   constructor() {
-    // Initialize GridRenderer with config
+    // Initialize GridRenderer and StyleManager with config
     this.gridRenderer = new GridRenderer();
+    this.styleManager = new GridStyleManager();
     this.init();
   }
   
@@ -85,6 +88,9 @@ export class GridManager {
       return;
     }
     
+    // Update CSS variables first
+    this.styleManager.updateGridStyles(this.resourceData);
+    
     // Delegate to GridRenderer with current view context
     this.gridRenderer.renderGrid(
       this.container,