Include question text in idle_prompt notification

Feature request

When Claude Code sends a notification (idle_prompt), the notification body only says something generic like "Claude is waiting for your response" — with no context about what is being asked.

Problem

If the user has switched to another window or app while Claude is working, they receive the notification but have no idea what question Claude asked. They have to go back to the terminal to read it, which defeats part of the purpose of the notification.

Suggested improvement

Include the beginning of the assistant's last message (e.g. first 150–200 characters) in the notification body.

Example — current:

Claude is waiting for your response

Example — improved:

Claude is waiting: "I found two possible approaches. Which do you prefer? 1) modify the existing function 2) create a new one"

Notes

• The last_assistant_message field is already present in the Stop hook payload — if it's also available in the Notification hook payload, this would be a low-effort addition.
• A length cap (e.g. 200 chars) would keep notifications readable.
• This is especially useful during long tasks where the user moves to other work while Claude is processing.