Function default_operation_timeout 

pub fn default_operation_timeout(chat_timeout: Duration) -> Duration

Safety-net timeout for a single send_command round-trip.

This is the outer Rust-side timeout that wraps all commands sent to the Python thread (chat, create_agent, cancel, get_history, …). The Python side applies its own, tighter timeouts (chat_timeout, HANDLER_TIMEOUT), so this value should only fire if the Python thread is completely stuck.

Defaults to chat_timeout + 2 minutes to give inner timeouts room to fire first.