Refactors event handling and grid rendering

Improves calendar performance and data flow by streamlining event emissions and grid rendering logic.

- Replaces generic CONFIG_UPDATE events with REFRESH_REQUESTED
  for more specific refresh triggers.
- Removes redundant grid re-renders on DATE_CHANGED and
  WEEK_CHANGED events, delegating navigation to NavigationManager.
- Introduces VIEW_CHANGED and DATE_CHANGED events for calendar
  mode and date selection, respectively.
- NavigationManager now handles date validation.
- Moves rendering logic from NavigationManager to NavigationRenderer.
- Syncs scroll position based on PERIOD_CHANGED instead of
  NAVIGATION_ANIMATION_COMPLETE.

This change optimizes the calendar's responsiveness and reduces
unnecessary re-renders, leading to a smoother user experience.

src/managers/NavigationManager.ts

@@ -35,7 +35,7 @@ export class NavigationManager {
 
   private setupEventListeners(): void {
     // Initial DOM update when calendar is initialized
-    this.eventBus.on(CoreEvents.CALENDAR_INITIALIZED, () => {
+    this.eventBus.on(CoreEvents.INITIALIZED, () => {
       console.log('NavigationManager: Received CALENDAR_INITIALIZED, updating week info');
       this.updateWeekInfo();
     });
@@ -63,9 +63,22 @@ export class NavigationManager {
     });
 
     // Listen for external navigation requests
-    this.eventBus.on(CoreEvents.NAVIGATE_TO_DATE, (event: Event) => {
+    this.eventBus.on(CoreEvents.DATE_CHANGED, (event: Event) => {
       const customEvent = event as CustomEvent;
-      const targetDate = new Date(customEvent.detail.date);
+      const dateFromEvent = customEvent.detail.date || customEvent.detail.currentDate;
+      
+      // Validate date before processing
+      if (!dateFromEvent) {
+        console.warn('NavigationManager: No date provided in DATE_CHANGED event', customEvent.detail);
+        return;
+      }
+      
+      const targetDate = new Date(dateFromEvent);
+      if (isNaN(targetDate.getTime())) {
+        console.warn('NavigationManager: Invalid date in DATE_CHANGED event', dateFromEvent);
+        return;
+      }
+      
       this.navigateToDate(targetDate);
     });
   }
@@ -189,10 +202,6 @@ export class NavigationManager {
       
       // Update week info and notify other managers
       this.updateWeekInfo();
-      this.eventBus.emit(CoreEvents.WEEK_CHANGED, {
-        weekStart: this.currentWeek,
-        weekEnd: this.dateCalculator.addDays(this.currentWeek, 6)
-      });
 
       // Emit period change event for ScrollManager
       this.eventBus.emit(CoreEvents.PERIOD_CHANGED, {
@@ -247,11 +256,6 @@ export class NavigationManager {
     this.currentWeek = new Date(weekStart);
     this.targetWeek = new Date(weekStart);
     this.updateWeekInfo();
-    
-    this.eventBus.emit(CoreEvents.WEEK_CHANGED, {
-      weekStart: this.currentWeek,
-      weekEnd: DateUtils.addDays(this.currentWeek, 6)
-    });
   }
 
   // Rendering methods moved to NavigationRenderer for better separation of concerns