refactor(auth): replace print statements with logging in SimpleAuthTokenService

- Inject Logger into SimpleAuthTokenService
- Replace print statements with appropriate log levels
- Update log messages to use logging conventions
- Remove unnecessary print statements and use logging for all output

Author: fulleni

lib/src/services/simple_auth_token_service.dart

@@ -1,6 +1,7 @@
 import 'package:ht_api/src/services/auth_token_service.dart';
 import 'package:ht_data_repository/ht_data_repository.dart';
 import 'package:ht_shared/ht_shared.dart';
+import 'package:logging/logging.dart';
 
 /// {@template simple_auth_token_service}
 /// A minimal, dependency-free implementation of [AuthTokenService] for debugging.
@@ -10,63 +11,61 @@ import 'package:ht_shared/ht_shared.dart';
 /// {@endtemplate}
 class SimpleAuthTokenService implements AuthTokenService {
   /// {@macro simple_auth_token_service}
-  const SimpleAuthTokenService({required HtDataRepository<User> userRepository})
-    : _userRepository = userRepository;
+  const SimpleAuthTokenService({
+    required HtDataRepository<User> userRepository,
+    required Logger log,
+  })  : _userRepository = userRepository,
+        _log = log;
 
   final HtDataRepository<User> _userRepository;
+  final Logger _log;
   static const String _tokenPrefix = 'valid-token-for-user-id:';
 
   @override
   Future<String> generateToken(User user) async {
-    print('[SimpleAuthTokenService] Generating token for user ${user.id}');
+    _log.info('Generating token for user ${user.id}');
     final token = '$_tokenPrefix${user.id}';
-    print('[SimpleAuthTokenService] Generated token: $token');
+    _log.finer('Generated token: $token');
     // Simulate async operation if needed, though not strictly necessary here
     await Future<void>.delayed(Duration.zero);
     return token;
   }
 
   @override
   Future<User?> validateToken(String token) async {
-    print('[SimpleAuthTokenService] Attempting to validate token: $token');
+    _log.finer('Attempting to validate token: $token');
     if (!token.startsWith(_tokenPrefix)) {
-      print('[SimpleAuthTokenService] Validation failed: Invalid prefix.');
+      _log.warning('Validation failed: Invalid prefix.');
       // Mimic JWT behavior by throwing Unauthorized for invalid format
       throw const UnauthorizedException('Invalid token format.');
     }
 
     final userId = token.substring(_tokenPrefix.length);
-    print('[SimpleAuthTokenService] Extracted user ID: $userId');
+    _log.finer('Extracted user ID: $userId');
 
     if (userId.isEmpty) {
-      print('[SimpleAuthTokenService] Validation failed: Empty user ID.');
+      _log.warning('Validation failed: Empty user ID.');
       throw const UnauthorizedException('Invalid token: Empty user ID.');
     }
 
     try {
-      print(
-        '[SimpleAuthTokenService] Attempting to read user from repository...',
-      );
+      _log.finer('Attempting to read user from repository...');
       final user = await _userRepository.read(id: userId);
-      print('[SimpleAuthTokenService] User read successful: ${user.id}');
+      _log.info('User read successful: ${user.id}');
       return user;
     } on NotFoundException {
-      print(
-        '[SimpleAuthTokenService] Validation failed: User ID $userId not found.',
-      );
+      _log.warning('Validation failed: User ID $userId not found.');
       // Return null if user not found, mimicking successful validation
       // of a token for a non-existent user. The middleware handles this.
       return null;
     } on HtHttpException catch (e, s) {
       // Handle other potential repository errors
-      print(
-        '[SimpleAuthTokenService] Validation failed: Repository error $e\n$s',
-      );
+      _log.warning('Validation failed: Repository error', e, s);
       // Re-throw other client/repo exceptions
       rethrow;
     } catch (e, s) {
       // Catch unexpected errors during validation
-      print('[SimpleAuthTokenService] Unexpected validation error: $e\n$s');
+      _log.severe('Unexpected validation error', e, s);
       throw OperationFailedException(
         'Simple token validation failed unexpectedly: $e',
       );
@@ -78,8 +77,8 @@ class SimpleAuthTokenService implements AuthTokenService {
     // This service uses simple prefixed tokens, not JWTs with JTI.
     // True invalidation/blacklisting isn't applicable here.
     // This method is implemented to satisfy the AuthTokenService interface.
-    print(
-      '[SimpleAuthTokenService] Received request to invalidate token: $token. '
+    _log.info(
+      'Received request to invalidate token: $token. '
       'No server-side invalidation is performed for simple tokens.',
     );
     // Simulate async operation