Design a Global E-Commerce Backend System

Design a **global e-commerce system** with cart, inventory, catalog, and order workflow.

Include:
1. Microservices boundaries
2. Cart service caching strategy
3. Inventory reservation workflow
4. Order lifecycle orchestration
5. Search & indexing using Elasticsearch
6. Price service with dynamic rules
7. Checkout system with payment provider abstraction
8. Multiregion data replication
9. Shipping integration flows
10. Scalability & fault isolation model