Function is_transient 

pub fn is_transient(err: &AcpCliError) -> bool

Returns true for errors that are safe to retry (network/connection failures before any agent output was produced). This includes agent process spawn failures, ACP initialization/session-creation failures, and bridge channel closures — all mapped to Connection in the bridge layer.

Non-retriable errors include semantic ACP failures (permission denied, session not found), user-initiated interrupts, timeouts (which may imply partial side effects), and I/O errors unrelated to the network layer.