Run `notify` hook for approval-request events (not only turn completion)

Summary

notify currently appears to run only after an agent turn completes. I’d like it to also run when an approval is requested (for command/file-change/apply-patch approvals).

Why this matters

I rely on notify to send email alerts when Codex needs input. Right now I receive emails for agent responses, but not when Codex pauses waiting for approval.

Current behavior

• notify = ["uv", "run", "/home/.../.codex/notify.py"] works for turn completion events.
• No notify invocation occurs when approval is requested.
• [tui].notifications = ["agent-turn-complete", "approval-requested"] helps for desktop notifications, but it does not trigger the external notify hook.

Requested behavior

Please trigger the external notify hook for approval-request lifecycle events as well, for example:

• command execution approval requested
• file change / patch approval requested
• any other user-approval prompt that blocks execution

Suggested payload shape

Either:

1. Extend the existing payload with "type": "approval-requested" and include request details, or
2. Keep backward compatibility and add a second hook/event specifically for approvals.

Backward compatibility

If existing users depend on turn-complete-only behavior, this could be gated by a config flag (default on/off as you see fit).