Refactors calendar configuration and event handling

Streamlines calendar configuration by adopting a singleton pattern for consistent access and simplifies event handling.

- Removes direct `CalendarConfig` dependency injection in favor of the `calendarConfig` singleton, reducing code complexity.
- Replaces specific event emissions for grid, date, and resource settings updates with a general `REFRESH_REQUESTED` event.
- Updates event names to be more descriptive and consistent ("NAVIGATION_COMPLETED", "PERIOD_INFO_UPDATE").
- Removes the need to pass the calendar config to renderers since it is now a singleton.

This improves code maintainability and simplifies the event emission process.

src/managers/DragDropManager.ts

@@ -4,7 +4,7 @@
  */
 
 import { IEventBus } from '../types/CalendarTypes';
-import { CalendarConfig } from '../core/CalendarConfig';
+import { calendarConfig } from '../core/CalendarConfig';
 import { DateCalculator } from '../utils/DateCalculator';
 
 interface CachedElements {
@@ -20,7 +20,6 @@ interface Position {
 
 export class DragDropManager {
   private eventBus: IEventBus;
-  private config: CalendarConfig;
   
   // Mouse tracking with optimized state
   private isMouseDown = false;
@@ -61,12 +60,11 @@ export class DragDropManager {
     return (this.snapIntervalMinutes / 60) * this.hourHeightPx;
   }
   
-  constructor(eventBus: IEventBus, config: CalendarConfig) {
+  constructor(eventBus: IEventBus) {
     this.eventBus = eventBus;
-    this.config = config;
-    
+
     // Get config values
-    const gridSettings = config.getGridSettings();
+    const gridSettings = calendarConfig.getGridSettings();
     this.hourHeightPx = gridSettings.hourHeight;
     
     this.init();