Refactors calendar data management and sync infrastructure

Introduces comprehensive data management system for calendar V2
- Adds IndexedDB storage with pluggable entity services
- Implements EventBus for decoupled event communication
- Creates data seeding mechanism for initial application setup
- Establishes sync and repository abstractions for flexible data handling

src/v2/storage/events/EventService.ts

@@ -0,0 +1,84 @@
+import { ICalendarEvent, EntityType, IEventBus } from '../../types/CalendarTypes';
+import { EventStore } from './EventStore';
+import { EventSerialization } from './EventSerialization';
+import { BaseEntityService } from '../BaseEntityService';
+import { IndexedDBContext } from '../IndexedDBContext';
+
+/**
+ * EventService - CRUD operations for calendar events in IndexedDB
+ *
+ * Extends BaseEntityService for shared CRUD and sync logic.
+ * Provides event-specific query methods.
+ */
+export class EventService extends BaseEntityService<ICalendarEvent> {
+  readonly storeName = EventStore.STORE_NAME;
+  readonly entityType: EntityType = 'Event';
+
+  constructor(context: IndexedDBContext, eventBus: IEventBus) {
+    super(context, eventBus);
+  }
+
+  protected serialize(event: ICalendarEvent): unknown {
+    return EventSerialization.serialize(event);
+  }
+
+  protected deserialize(data: unknown): ICalendarEvent {
+    return EventSerialization.deserialize(data as Record<string, unknown>);
+  }
+
+  /**
+   * Get events within a date range
+   */
+  async getByDateRange(start: Date, end: Date): Promise<ICalendarEvent[]> {
+    return new Promise((resolve, reject) => {
+      const transaction = this.db.transaction([this.storeName], 'readonly');
+      const store = transaction.objectStore(this.storeName);
+      const index = store.index('start');
+
+      const range = IDBKeyRange.lowerBound(start.toISOString());
+      const request = index.getAll(range);
+
+      request.onsuccess = () => {
+        const data = request.result as unknown[];
+        const events = data
+          .map(item => this.deserialize(item))
+          .filter(event => event.start <= end);
+        resolve(events);
+      };
+
+      request.onerror = () => {
+        reject(new Error(`Failed to get events by date range: ${request.error}`));
+      };
+    });
+  }
+
+  /**
+   * Get events for a specific resource
+   */
+  async getByResource(resourceId: string): Promise<ICalendarEvent[]> {
+    return new Promise((resolve, reject) => {
+      const transaction = this.db.transaction([this.storeName], 'readonly');
+      const store = transaction.objectStore(this.storeName);
+      const index = store.index('resourceId');
+      const request = index.getAll(resourceId);
+
+      request.onsuccess = () => {
+        const data = request.result as unknown[];
+        const events = data.map(item => this.deserialize(item));
+        resolve(events);
+      };
+
+      request.onerror = () => {
+        reject(new Error(`Failed to get events for resource ${resourceId}: ${request.error}`));
+      };
+    });
+  }
+
+  /**
+   * Get events for a resource within a date range
+   */
+  async getByResourceAndDateRange(resourceId: string, start: Date, end: Date): Promise<ICalendarEvent[]> {
+    const resourceEvents = await this.getByResource(resourceId);
+    return resourceEvents.filter(event => event.start >= start && event.start <= end);
+  }
+}