add support for initializing and resetting crypto identity

Fixes #137

lib/models/gomuks_exception.dart

@@ -6,6 +6,12 @@ class GomuksException implements Exception {
   String? get errorCode =>
       RegExp(r"^(M_[A-Z_]+)").firstMatch(message)?.group(1);
 
+  /// The HTTP status code of the failed request
+  int? get statusCode => switch (RegExp(r"HTTP (\d{3})").firstMatch(message)) {
+    final match? => int.parse(match.group(1)!),
+    null => null,
+  };
+
   @override
   String toString() => message;
 }