feat: Implement Step 10-11 - Statistics and Notification Services

Step 10: Data Analytics and Statistics Service
- Created comprehensive statistics service with real-time metrics collection
- Implemented time-series data storage interface (InfluxDB compatible)
- Added data aggregation and analytics endpoints
- Integrated Redis caching for performance optimization
- Made Kafka connection optional for resilience

Step 11: Real-time Notification System
- Built multi-channel notification service (Email, SMS, Push, In-App)
- Implemented priority-based queue management with Redis
- Created template engine for dynamic notifications
- Added user preference management for personalized notifications
- Integrated WebSocket server for real-time updates
- Fixed pymongo/motor compatibility issues (motor 3.5.1)

Testing:
- Created comprehensive test suites for both services
- Added integration test script to verify cross-service communication
- All services passing health checks and functional tests

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

docker-compose.yml

@@ -191,6 +191,64 @@ services:
       timeout: 5s
       retries: 5
 
+  # Notifications Service
+  notifications-backend:
+    build: 
+      context: ./services/notifications/backend
+      dockerfile: Dockerfile
+    container_name: site11-notifications-backend
+    ports:
+      - "8013:8000"
+    environment:
+      - MONGODB_URL=mongodb://mongodb:27017
+      - REDIS_URL=redis://redis:6379
+      - KAFKA_BOOTSTRAP_SERVERS=kafka:9092
+      - SMTP_HOST=${SMTP_HOST:-smtp.gmail.com}
+      - SMTP_PORT=${SMTP_PORT:-587}
+      - SMTP_USER=${SMTP_USER:-}
+      - SMTP_PASSWORD=${SMTP_PASSWORD:-}
+      - SMS_API_KEY=${SMS_API_KEY:-}
+      - SMS_API_URL=${SMS_API_URL:-}
+      - FCM_SERVER_KEY=${FCM_SERVER_KEY:-}
+    depends_on:
+      - mongodb
+      - redis
+      - kafka
+    networks:
+      - site11_network
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8000/health"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+
+  # Statistics Service
+  statistics-backend:
+    build: 
+      context: ./services/statistics/backend
+      dockerfile: Dockerfile
+    container_name: site11-statistics-backend
+    ports:
+      - "8012:8000"
+    environment:
+      - REDIS_URL=redis://redis:6379
+      - KAFKA_BOOTSTRAP_SERVERS=kafka:9092
+      - INFLUXDB_HOST=influxdb
+      - INFLUXDB_PORT=8086
+      - INFLUXDB_DATABASE=statistics
+    depends_on:
+      - redis
+      - kafka
+    networks:
+      - site11_network
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8000/health"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+
 networks:
   site11_network:
     driver: bridge