Module runtime 

Top-level orchestration: choose a shell backend, build the agent, run a task. Shared by the CLI (bin/aacode) and the FFI layer (ffi.rs).

Backend selection (config.shell_backend):

• Auto (default) — native OS shell on desktop, fastshell sandbox on mobile.
• Native — force the real OS shell (sh -c / cmd /C).
• Fastshell — force the sandbox engine (VFS jail + embedded CPython).

Structs

AgentRuntime

A prepared agent runtime bound to a project directory + shell backend.