fix: add AT&T Center alias for Frost Bank Center

NBA scraper now resolves old stadium name to current Spurs arena.
The AT&T Center was renamed to Frost Bank Center in July 2024.

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

Scripts/stadium_aliases.json

@@ -1325,6 +1325,12 @@
     "valid_from": "2002-10-01",
     "valid_until": "2023-10-01"
   },
+  {
+    "alias_name": "at&t center",
+    "stadium_canonical_id": "stadium_nba_frost_bank_center",
+    "valid_from": "2002-10-18",
+    "valid_until": "2024-07-01"
+  },
   {
     "alias_name": "vivint arena",
     "stadium_canonical_id": "stadium_nba_delta_center",