feat(sync): add CloudKit sync for dynamic sports

- Add CKSport model to parse CloudKit Sport records
- Add fetchSportsForSync() to CloudKitService for delta fetching
- Add syncSports() and mergeSport() to CanonicalSyncService
- Update DataProvider with dynamicSports support and allSports computed property
- Update MockAppDataProvider with matching dynamic sports support
- Add comprehensive documentation for adding new sports

The app can now sync sport definitions from CloudKit, enabling new sports
to be added without app updates. Sports are fetched, merged into SwiftData,
and exposed via AppDataProvider.allSports alongside built-in Sport enum cases.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

TO-DOS.md

@@ -24,12 +24,9 @@ read docs/TEST_PLAN.md in full
 question: do we need sync schedules anymore in settings
 
 // things that are new
-need to plan: build ios in app purchase for storekit
-need to plan: build complete receipt checking system to check if the user has purchased any subscriptions setting a value that can easily be checked anywhere in the app
-need to plan: use frontend-design skill to redesign the app
+
 
 // new ish to existing features
-feature: add the ability to add sports from cloudKit. name, icon, stadiums, etc
 
 // bugs
 Issue: sharing looks really dumb. need to be able to share achievements, league progress, and a trip