Show the exact expiration time and timezone on reset cards

What variant of Codex are you using?

Codex app

What feature would you like to see?

Reset cards currently show a calendar date such as Expires 8/1, but a date alone does not identify the actual cutoff instant.

Please display a complete expiration timestamp for every reset card, including an explicit timezone or UTC offset. For example:

Expires Aug 1, 2026 at 11:59:59 PM GMT+8

The exact presentation can follow the user's locale, but it should:

• Include both the date and time.
• Identify the timezone unambiguously (for example, GMT+8, UTC, or a timezone name together with its offset).
• Represent the same expiration instant consistently across the Codex app and other usage surfaces.
• Optionally expose the UTC value in a tooltip or secondary label when the primary value is localized.
• Make the cutoff semantics clear, such as whether the reset remains usable through the displayed second.

Why this matters

A date-only label is ambiguous for users in different regions and can be interpreted as meaning the reset remains valid until the end of that local calendar day. Users cannot reliably plan when to redeem a reset if the underlying expiration may occur earlier in the day or is calculated in another timezone.

Showing the exact timestamp would remove guesswork, prevent avoidable loss of unused resets, and make expiration behavior easier to understand and verify.

Acceptance criteria

• A user can determine the precise expiration instant without relying on undocumented timezone assumptions.
• The displayed value remains correct across locale, timezone, and daylight-saving changes.
• No reset card displays only a date when it can expire at a specific time during that date.

Related issues

• #28161 requests better expiration visibility and countdowns.
• #32540 reports a reset disappearing during the displayed expiration date and highlights the missing time/timezone information.

This request is specifically focused on making the expiration instant unambiguous in the UI.