implement backend skeleton with MongoDB and Claude AI integration

- Add controllers (Auth, Chat, Event) with placeholder implementations
- Add services (Auth, Chat, Event) with business logic interfaces
- Add repositories with MongoDB/Mongoose models (User, Event, Chat)
- Add middleware for JWT authentication
- Add Claude AI adapter implementing AIProvider interface
- Add utility modules for JWT and password handling
- Add shared types and DTOs for User, CalendarEvent, ChatMessage
- Configure routes with proper endpoint structure
- Update app.ts with dependency injection setup
- Add required dependencies: mongoose, bcrypt, jsonwebtoken, @anthropic-ai/sdk

apps/server/src/repositories/mongo/MongoEventRepository.ts

@@ -0,0 +1,29 @@
+import { CalendarEvent, CreateEventDTO, UpdateEventDTO } from '@caldav/shared';
+import { EventRepository } from '../../services/interfaces';
+import { EventModel } from './models';
+
+export class MongoEventRepository implements EventRepository {
+  async findById(id: string): Promise<CalendarEvent | null> {
+    throw new Error('Not implemented');
+  }
+
+  async findByUserId(userId: string): Promise<CalendarEvent[]> {
+    throw new Error('Not implemented');
+  }
+
+  async findByDateRange(userId: string, startDate: Date, endDate: Date): Promise<CalendarEvent[]> {
+    throw new Error('Not implemented');
+  }
+
+  async create(userId: string, data: CreateEventDTO): Promise<CalendarEvent> {
+    throw new Error('Not implemented');
+  }
+
+  async update(id: string, data: UpdateEventDTO): Promise<CalendarEvent | null> {
+    throw new Error('Not implemented');
+  }
+
+  async delete(id: string): Promise<boolean> {
+    throw new Error('Not implemented');
+  }
+}