fix(data): populate stadium timezone in scrapers and CloudKit sync

Stadium timezones were always null because scrapers weren't passing
the timezone from STADIUM_MAPPINGS to the Stadium constructor. This
fix propagates timezone data through the entire pipeline: scrapers,
CloudKit uploader, and Swift CloudKit model.

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

SportsTime/Core/Models/CloudKit/CKModels.swift

@@ -119,6 +119,7 @@ struct CKStadium {
     static let yearOpenedKey = "yearOpened"
     static let imageURLKey = "imageURL"
     static let sportKey = "sport"
+    static let timezoneIdentifierKey = "timezoneIdentifier"
 
     let record: CKRecord
 
@@ -160,6 +161,7 @@ struct CKStadium {
         let imageURL = (record[CKStadium.imageURLKey] as? String).flatMap { URL(string: $0) }
         let sportRaw = record[CKStadium.sportKey] as? String ?? "MLB"
         let sport = Sport(rawValue: sportRaw) ?? .mlb
+        let timezoneIdentifier = record[CKStadium.timezoneIdentifierKey] as? String
 
         return Stadium(
             id: id,
@@ -171,7 +173,8 @@ struct CKStadium {
             capacity: capacity,
             sport: sport,
             yearOpened: record[CKStadium.yearOpenedKey] as? Int,
-            imageURL: imageURL
+            imageURL: imageURL,
+            timeZoneIdentifier: timezoneIdentifier
         )
     }
 }