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/CalendarManager.ts

@@ -144,6 +144,7 @@ export class CalendarManager {
         this.eventBus.emit(CoreEvents.DATE_CHANGED, {
             previousDate,
             currentDate: this.currentDate,
+            date: this.currentDate,  // Add for backward compatibility
             view: this.currentView
         });