fix(data): add timezone handling for Sports-Reference scrapers and new stadiums

- Add ET timezone (America/New_York) to all Sports-Reference scrapers:
  - NBA: Basketball-Reference times parsed as ET
  - NFL: Pro-Football-Reference times parsed as ET
  - NHL: Hockey-Reference times parsed as ET
  - MLB: Baseball-Reference times parsed as ET
- Document source timezones in scraper docstrings
- Add 11 new stadiums to STADIUM_MAPPINGS:
  - NFL: 5 international venues (Corinthians Arena, Croke Park,
    Olympic Stadium Berlin, Santiago Bernabéu, Tom Benson Hall of Fame)
  - MLS: 4 alternate venues (Miami Freedom Park, Citi Field,
    LA Memorial Coliseum, M&T Bank Stadium)
  - NWSL: 2 alternate venues (Northwestern Medicine Field, ONE Spokane)
- Add 15 stadium aliases for MLS/NWSL team-based lookups
- Fix CanonicalSyncService to sync timezone identifier to SwiftData
- Update debug logging to use stadium timezone for display

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

SportsTime/Features/Schedule/ViewModels/ScheduleViewModel.swift

@@ -120,7 +120,7 @@ final class ScheduleViewModel {
             let nbaGames = games.filter { $0.game.sport == .nba }
             print("🏀 [DEBUG] All NBA games in schedule (\(nbaGames.count) total):")
             for game in nbaGames.sorted(by: { $0.game.dateTime < $1.game.dateTime }) {
-                let dateStr = game.game.dateTime.formatted(date: .abbreviated, time: .shortened)
+                let dateStr = game.game.dateTime.gameDateTimeString(in: game.stadium.timeZone)
                 print("🏀   \(dateStr): \(game.awayTeam.name) @ \(game.homeTeam.name) (\(game.game.id))")
             }