AgentFS with copy-on-write overlay filesystem

AgentFS introduces a filesystem abstraction tailored for agents, emphasizing auditability, reproducibility, and portability, achieved through a copy-on-write overlay filesystem. This system allows users to isolate agent activities by creating a SQLite-backed filesystem that interacts with the host filesystem without altering it, using an SDK compatible with TypeScript, Python, and Rust. The agentfs run command facilitates this process by mounting the host filesystem to a sandbox environment, where file modifications by agents are isolated to a writable delta layer, preserving the integrity of the host system. On Linux, this is implemented using FUSE and namespaces, while macOS employs NFS and sandbox-exec for similar functionality, ensuring agents can operate without affecting host files. This approach allows agents to work on shared source code while maintaining separate environments, supporting a seamless development workflow without compromising system stability.