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>

SportsTime.xcodeproj/xcshareddata/xcschemes/SportsTime.xcscheme

@@ -42,8 +42,7 @@
             </BuildableReference>
          </TestableReference>
          <TestableReference
-            skipped = "NO"
-            parallelizable = "NO">
+            skipped = "NO">
             <BuildableReference
                BuildableIdentifier = "primary"
                BlueprintIdentifier = "1CA7F90D2F0D647400490ABD"