pydantic-ai 2.40.0 makes voice agents interruptible.

The September 5 release adds handle_barge_in=True, interrupt(played_bytes=...) and played_audio_bytes to the realtime session, plus RealtimeSession.enqueue() for out-of-band prompts from driving code and respond= on send(). It adds @agent.on_event for registering listeners on an Agent, and fixes a realtime tool wedging itself instead of hanging up via ctx.realtime_session.close(). The prior day's 2.39.0 added gpt-6-astra and Azure content-filter error detection (GitHub).