bug: inconsistent time format (UI)

[leobrqz]

Summary

Settings → Display → Time format → 24-hour does not apply across the app. Many screens still show AM/PM.

Cause

Clock times only respect the setting when rendered through formatTime / formatTimeRange in frontend/apps/web/lib/display.ts and the component passes timeFormat from usePreference("display.timeFormat", …).

Today that happens only in:

• frontend/apps/web/app/calendar/page.tsx (Appointments table time column)
• frontend/apps/web/components/AppointmentListDialog.tsx (appointment list rows)

All other time UI ignores display.timeFormat.

Defects

1. StageHistoryDialog (frontend/apps/web/components/StageHistoryDialog.tsx): timestamps use Intl.DateTimeFormat("en-US", { … hour, minute }) without hour12. Default for that locale is 12-hour. display.locale is not used.

2. Schedule-X (frontend/apps/web/app/calendar/page.tsx, frontend/apps/web/app/dashboard/CalendarStrip.tsx): month grid, agenda, and dashboard week strip render event times inside the library. That path does not use formatTime / formatTimeRange or display.timeFormat. CalendarStrip also does not use display.locale.

Requirements

• Every user-visible clock time must follow display.timeFormat and display.locale (shared helpers in display.ts or equivalent, with explicit hour12).
• Third-party calendars must be configured or customized so event times follow the same rules.
• StageHistoryDialog must stop using a hardcoded en-US formatter without hour12.

Acceptance criteria

• With 24-hour selected: no AM/PM in stage history, Schedule-X surfaces, dashboard week strip, or any other time label in the app.
• With 12-hour selected: AM/PM where appropriate.
• Changing locale in Settings does not leave hardcoded en-US formatters on dated/time strings meant to respect that setting.