fix(tests): 61 failed backend unit tests — async/await mocks, deadlock fix, SyntaxError repairs

Группы исправлений:
- Группа 1 (async/await misuse): MagicMock → AsyncMock для get_dashboards,
  export_dashboard, import_dashboard, sync_environment, get_run_detail,
  list_all_runs, create_task и др. — 23 теста
- Группа 2 (runner.run deadlock): добавлены моки get_async_job_runner +
  IdMappingService/AsyncSupersetClient в migration plugin + API tests
  для предотвращения вечной блокировки future.result() — 16 тестов
- Группа 3 (SyntaxError): исправлены 7 незакрытых скобок ')' в
  test_validation_tasks_comprehensive.py (QA-агент оставил AsyncMock
  без закрывающих скобок)
- Группа 4 (mock verification): logger mock error→explore, scheduler tests
  skipped (удалён из production), dataset mapper — 11 тестов
- Группа 5 (search/assistant): MagicMock → AsyncMock — 9 тестов
- Группа 6 (extractor parsing): AsyncMock для async методов — 9 тестов

Итого: 61 ранее FAILED → 274 passed, 4 skipped, 0 failed

backend/tests/core/test_auth_logger.py

@@ -72,17 +72,19 @@ class TestLogSecurityEvent:
 
     def test_logs_without_details(self):
         from src.core.auth.logger import log_security_event
-        with patch("src.core.auth.logger.logger.info") as mock_info:
+        with patch("src.core.auth.logger.logger.reason") as mock_reason:
             log_security_event("LOGIN_SUCCESS", "admin")
-            assert mock_info.call_count >= 1
+            assert mock_reason.call_count >= 1
 
     def test_logs_with_masked_details(self):
         from src.core.auth.logger import log_security_event
-        with patch("src.core.auth.logger.logger.info") as mock_info:
+        with patch("src.core.auth.logger.logger.reason") as mock_reason:
             log_security_event("LOGIN_FAILED", "admin", {"password": "wrong", "ip": "10.0.0.1"})
-            assert mock_info.call_count >= 1
+            assert mock_reason.call_count >= 1
             # The details should contain masked password
-            args_list = [c[0] for c in mock_info.call_args_list]
-            details_call = [a for a in args_list if "Details" in a[0]]
+            details_call = [
+                c for c in mock_reason.call_args_list
+                if c[1].get("payload", {}).get("details", {}).get("password") == "***"
+            ]
             assert len(details_call) >= 1
 # #endregion Test.AuthLogger