Improves performance by caching DOM elements

Caches frequently accessed DOM elements in NavigationManager and
EventRenderer to reduce redundant queries, improving performance.

Updates the event renderer to trigger all-day height animations and
introduces a destroy method for resource management.

Refactors time formatting in EventRenderer to handle both total
minutes and Date objects using a unified method.

src/managers/NavigationManager.ts

@@ -16,6 +16,10 @@ export class NavigationManager {
   private currentWeek: Date;
   private targetWeek: Date;
   private animationQueue: number = 0;
+  
+  // Cached DOM elements to avoid redundant queries
+  private cachedCalendarContainer: HTMLElement | null = null;
+  private cachedCurrentGrid: HTMLElement | null = null;
 
   constructor(eventBus: IEventBus, eventRenderer: EventRenderingService) {
     this.eventBus = eventBus;
@@ -31,6 +35,37 @@ export class NavigationManager {
     // Don't update week info immediately - wait for DOM to be ready
   }
 
+  /**
+   * Get cached calendar container element
+   */
+  private getCalendarContainer(): HTMLElement | null {
+    if (!this.cachedCalendarContainer) {
+      this.cachedCalendarContainer = document.querySelector('swp-calendar-container');
+    }
+    return this.cachedCalendarContainer;
+  }
+
+  /**
+   * Get cached current grid element
+   */
+  private getCurrentGrid(): HTMLElement | null {
+    const container = this.getCalendarContainer();
+    if (!container) return null;
+    
+    if (!this.cachedCurrentGrid) {
+      this.cachedCurrentGrid = container.querySelector('swp-grid-container:not([data-prerendered])');
+    }
+    return this.cachedCurrentGrid;
+  }
+
+  /**
+   * Clear cached DOM elements (call when DOM structure changes)
+   */
+  private clearCache(): void {
+    this.cachedCalendarContainer = null;
+    this.cachedCurrentGrid = null;
+  }
+
   private setupEventListeners(): void {
     // Initial DOM update when calendar is initialized
     this.eventBus.on(CoreEvents.INITIALIZED, () => {
@@ -137,8 +172,8 @@ export class NavigationManager {
    * Animation transition using pre-rendered containers when available
    */
   private animateTransition(direction: 'prev' | 'next', targetWeek: Date): void {
-    const container = document.querySelector('swp-calendar-container');
-    const currentGrid = container?.querySelector('swp-grid-container:not([data-prerendered])');
+    const container = this.getCalendarContainer();
+    const currentGrid = this.getCurrentGrid();
     
     if (!container || !currentGrid) {
       return;
@@ -148,7 +183,7 @@ export class NavigationManager {
     let newGrid: HTMLElement;
 
     // Always create a fresh container for consistent behavior
-    newGrid = this.navigationRenderer.renderContainer(container as HTMLElement, targetWeek);
+    newGrid = this.navigationRenderer.renderContainer(container, targetWeek);
 
     
     // Clear any existing transforms before animation
@@ -187,6 +222,9 @@ export class NavigationManager {
       newGrid.style.position = 'relative';
       newGrid.removeAttribute('data-prerendered');
       
+      // Clear cache since DOM structure changed
+      this.clearCache();
+      
       // Update state
       this.currentWeek = new Date(targetWeek);
       this.animationQueue--;