Fix game times with UTC data, restructure schedule by date

- Update games_canonical.json to use ISO 8601 UTC timestamps (game_datetime_utc)
- Fix BootstrapService timezone-aware parsing for venue-local fallback
- Fix thread-unsafe shared DateFormatter in RichGame local time display
- Bump SchemaVersion to 4 to force re-bootstrap with correct UTC data
- Restructure schedule view: group by date instead of sport, with sport
  icons on each row and date section headers showing game counts
- Fix schedule row backgrounds using Theme.cardBackground instead of black
- Sort games by UTC time with local-time tiebreaker for same-instant games

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

SportsTimeTests/Export/POISearchServiceTests.swift

@@ -24,7 +24,8 @@ struct POITests {
             category: .restaurant,
             coordinate: CLLocationCoordinate2D(latitude: 40.0, longitude: -74.0),
             distanceMeters: distanceMeters,
-            address: nil
+            address: nil,
+            mapItem: nil
         )
     }