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/renderers/HeaderRenderer.ts

@@ -25,7 +25,7 @@ export interface HeaderRenderContext {
  * Date-based header renderer (original functionality)
  */
 export class DateHeaderRenderer implements HeaderRenderer {
-  private dateCalculator: DateCalculator;
+  private dateCalculator!: DateCalculator;
 
   render(calendarHeader: HTMLElement, context: HeaderRenderContext): void {
     const { currentWeek, config, allDayEvents = [] } = context;
@@ -34,7 +34,7 @@ export class DateHeaderRenderer implements HeaderRenderer {
     this.dateCalculator = new DateCalculator(config);
     
     const dates = this.dateCalculator.getWorkWeekDates(currentWeek);
-    const weekDays = config.get('weekDays');
+    const weekDays = config.getDateViewSettings().weekDays;
     const daysToShow = dates.slice(0, weekDays);
 
     daysToShow.forEach((date, index) => {
@@ -62,7 +62,7 @@ export class DateHeaderRenderer implements HeaderRenderer {
     const { currentWeek, config, allDayEvents = [] } = context;
     
     const dates = this.dateCalculator.getWorkWeekDates(currentWeek);
-    const weekDays = config.get('weekDays');
+    const weekDays = config.getDateViewSettings().weekDays;
     const daysToShow = dates.slice(0, weekDays);
 
     // Process each all-day event to calculate its span