## Summary
- Adds `useHasMounted` hook (using `useSyncExternalStore` — no extra render cycle) to gate UTC timestamp formatting to client-only
- Fixes the visible time-flip in `EventSchedule` and `UpcomingCalendarPanel` where SSR rendered UTC time (e.g. "9:00 PM") and the client re-rendered with local time (e.g. "2:00 PM PDT") after hydration, with `suppressHydrationWarning` silently hiding the mismatch
- Fixes `formatEventDate` in `date-utils.ts` (and `EventSchedule`'s private copy) to parse `YYYY-MM-DD` strings as local midnight instead of UTC midnight, correcting an off-by-one day bug for UTC-negative users across all callers
## Test plan
- [ ] Navigate to a sports season page — confirm event times show in local timezone with no flash/flip on load
- [ ] Hard-reload the page — confirm no brief UTC time visible before settling on local time
- [ ] Check the home page `UpcomingCalendarPanel` — confirm same behavior
- [ ] Verify dates display correctly (e.g. no "Jun 17" showing for a "Jun 18" event near midnight UTC)
Co-authored-by: Chris Parsons <chrisparsons1127@gmail.com>
Reviewed-on: #95
