TL;DR — Distributed Lock Manager

Design a distributed lock manager that provides mutual exclusion across processes running on different machines. When multiple services need to access a shared resource (database row, file, external API with rate limit), they must coordinate to ensure only one process holds the lock at a time. The system must handle node failures, network partitions, and clock skew gracefully. Key features: Acquire a named lock with TTL (auto-expire). Release a lock explicitly by the holder.