Design the architecture for a global, real-time messaging platform that must handle 100 million concurrent users with end-to-end latency under 100ms. Describe the data partitioning strategy, replication model, consensus algorithm selection, and approach to handling network partitions (CAP theorem trade-offs). Explain how you would implement eventual consistency for message ordering while ensuring durability. Do not use code; provide a detailed technical narrative explaining the components and their interactions.