Automatically redeem unused banked resets before they expire

What variant of Codex are you using?

Codex in the ChatGPT desktop app on macOS

What feature would you like to see?

Problem

A banked Codex rate-limit reset can expire unused if the user saves it for later but forgets to redeem it before the displayed expiration time.

Once the reset is about to expire, allowing it to disappear provides less value than applying it as a final fallback.

Proposed behavior

When a banked reset remains unused immediately before its expiration time, Codex should automatically redeem that specific reset.

This should be the default behavior:

1. Keep the reset available for manual redemption until expiry.
2. Do not redeem it early.
3. Automatically redeem it as the expiration fallback, even if the ChatGPT desktop app is closed.
4. Notify the user that the reset was redeemed automatically.

Additional information

This is distinct from #32218, which proposes letting users queue a reset for redemption when a usage limit is exhausted.

That request addresses unattended limit exhaustion. This request addresses a reset reaching its expiry unused. Both behaviours could coexist, with expiry redemption acting only as the final fallback.