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>

Scripts/sportstime_parser/scrapers/mls.py

@@ -27,7 +27,11 @@ class MLSScraper(BaseScraper):
 
     Sources (in priority order):
     1. ESPN API - Most reliable for MLS
-    2. FBref - Backup option
+    2. FBref - Backup option (not implemented)
+
+    Source Timezones:
+    - espn: UTC - ISO 8601 format with "Z" suffix
+    - fbref: Not implemented
     """
 
     def __init__(self, season: int, **kwargs):