fix(digital-id): завершать ЕСИА callback через EXTERNAL_CALLBACK

test/webapp_module_test.dart

@@ -0,0 +1,34 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:komet/backend/modules/webapp.dart';
+
+void main() {
+  group('ExternalCallbackResult', () {
+    test('parses callback response fields', () {
+      final result = ExternalCallbackResult.fromPayload({
+        'botId': '123456',
+        'startParam': 'esia-complete',
+      });
+
+      expect(result?.botId, 123456);
+      expect(result?.startParam, 'esia-complete');
+    });
+
+    test('parses a nested protocol response', () {
+      final result = ExternalCallbackResult.fromPayload({
+        'data': {'bot_id': 42, 'start_param': 'done'},
+      });
+
+      expect(result?.botId, 42);
+      expect(result?.startParam, 'done');
+    });
+
+    test('rejects a response without a bot id', () {
+      expect(
+        ExternalCallbackResult.fromPayload({
+          'data': {'startParam': 'done'},
+        }),
+        isNull,
+      );
+    });
+  });
+}