Refactor offline-first architecture with IndexedDB

Improves dependency injection and service initialization for IndexedDB-based calendar application

Implements lazy initialization for IndexedDB
Fixes race conditions in async event handling
Adds proper dependency injection with registerType
Enhances sync manager and repository pattern

Key improvements:
- Lazy database initialization
- Proper service lifecycle management
- Improved network awareness for sync operations
- Cleaned up initialization logic in index.ts

src/repositories/IndexedDBEventRepository.ts

@@ -23,8 +23,15 @@ export class IndexedDBEventRepository implements IEventRepository {
 
   /**
    * Load all events from IndexedDB
+   * Ensures IndexedDB is initialized and seeded on first call
    */
   async loadEvents(): Promise<ICalendarEvent[]> {
+    // Lazy initialization on first data load
+    if (!this.indexedDB.isInitialized()) {
+      await this.indexedDB.initialize();
+      await this.indexedDB.seedIfEmpty();
+    }
+
     return await this.indexedDB.getAllEvents();
   }