Remove date-only (@db.Date) treatment of initialDateScheduled

[Copilot]

initialDateScheduled is a full datetime, but several callsites were treating it as a @db.Date (midnight-UTC date-only) value — using formatDateOnly, dbDateToLocalDate, and UTC-based weekday lookup. This removes all that special-casing.

Changes

• EventCard.tsx: Drop isDateOnly flag, formatDateOnly import, UTC getWeekday path, and the @db.Date comment. Both initialDateScheduled and scheduledTimes now use formatEventDate uniformly.
• EventAvailabilityPage.tsx / AvailabilityScheduleView.tsx: Remove unused dbDateToLocalDate imports that were pulled in for the (incorrect) date-only handling.

Notes

Original PR: #3993

Test Cases

• Event card displays correct weekday/date when initialDateScheduled is set
• Event card displays correct weekday/date when only scheduledTimes is set

Screenshots

N/A — logic-only change, no visual difference intended

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