fix: replace Timestamp.toDate() with DateTime.tryParse in score list screens

score.createdAt is now String (ISO 8601) not Firebase Timestamp, so .toDate()
was a compile error. Use DateTime.tryParse() with fallback to DateTime.now().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/screens/lists/professional_score_list_screen.dart

@@ -94,7 +94,7 @@ class _ProfessionalScoreListScreenState
                                 ),
                                 const SizedBox(width: 5),
                                 Text(
-                                  '${score.createdAt.toDate().day}/${score.createdAt.toDate().month}/${score.createdAt.toDate().year}',
+                                  '${(DateTime.tryParse(score.createdAt) ?? DateTime.now()).day}/${(DateTime.tryParse(score.createdAt) ?? DateTime.now()).month}/${(DateTime.tryParse(score.createdAt) ?? DateTime.now()).year}',
                                   style: TextStyle(
                                     color: Colors.grey[600],
                                   ),

lib/screens/lists/user_score_list_screen.dart

@@ -93,7 +93,7 @@ class _UserScoreListScreenState extends State<UserScoreListScreen> {
                                 ),
                                 const SizedBox(width: 5),
                                 Text(
-                                  '${score.createdAt.toDate().day}/${score.createdAt.toDate().month}/${score.createdAt.toDate().year}',
+                                  '${(DateTime.tryParse(score.createdAt) ?? DateTime.now()).day}/${(DateTime.tryParse(score.createdAt) ?? DateTime.now()).month}/${(DateTime.tryParse(score.createdAt) ?? DateTime.now()).year}',
                                   style: TextStyle(
                                     color: Colors.grey[600],
                                   ),