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>

SportsTime/Core/Models/Local/CanonicalModels.swift

@@ -481,6 +481,66 @@ final class CanonicalGame {
     }
 }
 
+// MARK: - Canonical Sport
+
+@Model
+final class CanonicalSport {
+    @Attribute(.unique) var id: String
+    var abbreviation: String
+    var displayName: String
+    var iconName: String
+    var colorHex: String
+    var seasonStartMonth: Int
+    var seasonEndMonth: Int
+    var isActive: Bool
+    var lastModified: Date
+    var schemaVersion: Int
+    var sourceRaw: String
+
+    init(
+        id: String,
+        abbreviation: String,
+        displayName: String,
+        iconName: String,
+        colorHex: String,
+        seasonStartMonth: Int,
+        seasonEndMonth: Int,
+        isActive: Bool = true,
+        lastModified: Date = Date(),
+        schemaVersion: Int = SchemaVersion.current,
+        source: DataSource = .cloudKit
+    ) {
+        self.id = id
+        self.abbreviation = abbreviation
+        self.displayName = displayName
+        self.iconName = iconName
+        self.colorHex = colorHex
+        self.seasonStartMonth = seasonStartMonth
+        self.seasonEndMonth = seasonEndMonth
+        self.isActive = isActive
+        self.lastModified = lastModified
+        self.schemaVersion = schemaVersion
+        self.sourceRaw = source.rawValue
+    }
+
+    var source: DataSource {
+        get { DataSource(rawValue: sourceRaw) ?? .cloudKit }
+        set { sourceRaw = newValue.rawValue }
+    }
+
+    func toDomain() -> DynamicSport {
+        DynamicSport(
+            id: id,
+            abbreviation: abbreviation,
+            displayName: displayName,
+            iconName: iconName,
+            colorHex: colorHex,
+            seasonStartMonth: seasonStartMonth,
+            seasonEndMonth: seasonEndMonth
+        )
+    }
+}
+
 // MARK: - Bundled Data Timestamps
 
 /// Timestamps for bundled data files.