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>

Scripts/sportstime_parser/scrapers/nba.py

@@ -648,6 +648,7 @@ class NBAScraper(BaseScraper):
                 country=info.country,
                 latitude=info.latitude,
                 longitude=info.longitude,
+                timezone=info.timezone,
                 surface="hardwood",
                 roof_type="dome",
             )