VS Code extension: show notification/toast when waiting for user input

Feature Request

When Claude Code is running in the VS Code extension and reaches a point where it needs user attention (permission approval, question, tool confirmation), there is no visual notification outside the terminal panel. The user has to keep watching the terminal to know when input is needed.

Claude Code Desktop already shows system toast notifications in this situation, which is very helpful.

Requested behavior

When Claude Code is waiting for user input in VS Code:

1. Show a VS Code notification (vscode.window.showInformationMessage) with a message like "Claude Code is waiting for your input"
2. Optionally flash the terminal tab or show a badge indicator
3. Allow clicking the notification to focus the Claude Code terminal panel

Why this matters

During long-running tasks (code generation, multi-file edits, PR reviews), the user often switches to other tabs or applications. Without a notification, they don't know Claude is blocked waiting for permission, which wastes time on both sides.

Environment

• VS Code extension (not Desktop app or CLI)
• macOS / Windows / Linux