"Select a date and time range" popover uses AM/PM for "custom fixed date range", input field then displays 24 hour format (for me)

Bug Description

I was trying to use the "date and time range" popover in LLM Analytics. Via "Custom fixed date range..." I get to a date and time picker/chooser, and it uses AM/PM time format (after enabling time selection with "Include time?" checkbox). After selecting a time, it does show the selected duration in 24 hour format though (might just be only for me, as my browser asks for 24 hour format by default).

If you are on PostHog Cloud it would be really valuable if you can share any links where the problem occurs. This speeds up our ability to troubleshoot tremendously.

https://us.posthog.com/project/240542/llm-analytics/traces?date_from=2026-02-03T12%3A00%3A00&date_to=2026-02-03T13%3A00%3A00

How to reproduce

1. Go to LLM Analytics -> Traces
2. Open date/time chooser
3. Click "Custom fixed date range..." on the bottom
4. Enable time with "Include time?" by activating checkbox at bottom of popover
5. Observe the time input using AM and PM
6. Now select a time frame
7. Observe how the input field shows the time in 24 hour format when requested by the browser

Additional context

Debug info

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/019c572c-50ab-7fff-9f56-00401a287827?t=887
Admin: http://go/adminOrgUS/019a2f44-ec21-0000-2d2b-53a5221b9e8b (project ID 240542)

Start in LLM Analytics → Traces and reproduce the issue through the date/time chooser and its “Custom fixed date range...” flow. Compare the picker’s time format with the selected range input under a browser configured for 24-hour time; done means the two related controls use a consistent, expected format.