refactor(generator): история batch в Kafka вместо ClickHouse

- Зачем:
  - ревью rev5: ClickHouse-интеграция была проблемной (порт 9000 native vs HTTP,
    неработающий fallback, отсутствие DDL для базы meta)
  - архитектурно чище: генератор остаётся pure Kafka producer,
    история доступна для аналитики через стандартный ingestion
- Что:
  - удален ClickHouseBatchHistory, clickhouse-connect зависимость
  - добавлен KafkaBatchHistory с записью в топик generator_batch_history
  - добавлен BatchRecord.to_dict() для JSON-сериализации
  - добавлен рабочий fallback: Kafka → InMemory при недоступности
  - удален pytest-asyncio (не использовался)
  - добавлены тесты test_kafka_history.py (15 тестов) и test_service.py (6 тестов)
  - обновлена документация: топик вместо таблицы ClickHouse
- Проверка:
  - make generator-test: 44/44 тестов пройдено
  - docker-compose валиден, генератор не зависит от clickhouse

generator/tests/test_kafka_history.py

@@ -0,0 +1,263 @@
+"""
+Тесты для KafkaBatchHistory.
+"""
+
+from datetime import datetime, timezone
+from unittest.mock import MagicMock, patch
+
+import pytest
+from generator import BatchRecord, KafkaBatchHistory
+
+
+class TestBatchRecordSerialization:
+    """Тесты сериализации BatchRecord."""
+
+    def test_to_dict_serializes_all_fields(self):
+        """to_dict сериализует все поля."""
+        now = datetime(2024, 1, 15, 10, 30, 0, tzinfo=timezone.utc)
+        record = BatchRecord(
+            batch_id="abc123",
+            started_at=now,
+            finished_at=now,
+            sent_total=100,
+            sent_browser=25,
+            sent_location=25,
+            sent_device=25,
+            sent_geo=25,
+            status="success",
+            error_message=None,
+        )
+
+        data = record.to_dict()
+
+        assert data["batch_id"] == "abc123"
+        assert data["started_at"] == "2024-01-15T10:30:00+00:00"
+        assert data["finished_at"] == "2024-01-15T10:30:00+00:00"
+        assert data["sent_total"] == 100
+        assert data["sent_browser"] == 25
+        assert data["sent_location"] == 25
+        assert data["sent_device"] == 25
+        assert data["sent_geo"] == 25
+        assert data["status"] == "success"
+        assert data["error_message"] is None
+
+    def test_to_dict_with_error_message(self):
+        """to_dict сериализует error_message если есть."""
+        now = datetime.now(timezone.utc)
+        record = BatchRecord(
+            batch_id="err456",
+            started_at=now,
+            finished_at=now,
+            sent_total=0,
+            sent_browser=0,
+            sent_location=0,
+            sent_device=0,
+            sent_geo=0,
+            status="error",
+            error_message="Connection failed",
+        )
+
+        data = record.to_dict()
+
+        assert data["error_message"] == "Connection failed"
+
+    def test_isoformat_includes_timezone(self):
+        """ISO формат включает timezone."""
+        now = datetime.now(timezone.utc)
+        record = BatchRecord(
+            batch_id="tz789",
+            started_at=now,
+            finished_at=now,
+            sent_total=50,
+            sent_browser=12,
+            sent_location=13,
+            sent_device=12,
+            sent_geo=13,
+            status="partial",
+            error_message="Some errors",
+        )
+
+        data = record.to_dict()
+
+        # Должен содержать +00:00 или Z
+        assert "+" in data["started_at"] or "Z" in data["started_at"]
+
+
+class TestKafkaBatchHistory:
+    """Тесты KafkaBatchHistory."""
+
+    def test_history_topic_constant(self):
+        """Константа топика истории."""
+        assert KafkaBatchHistory.HISTORY_TOPIC == "generator_batch_history"
+
+    @patch("generator._import_kafka")
+    def test_init_connects_to_kafka(self, mock_import):
+        """Инициализация подключается к Kafka."""
+        mock_producer_class = MagicMock()
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+
+        assert history._initialized is True
+        assert history.bootstrap_servers == "localhost:9092"
+        mock_producer_class.assert_called_once()
+
+    @patch("generator._import_kafka")
+    def test_init_handles_connection_error(self, mock_import):
+        """Инициализация обрабатывает ошибку подключения."""
+        # Симулируем ошибку при создании producer
+        mock_producer_class = MagicMock(side_effect=Exception("Connection failed"))
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+
+        assert history._initialized is False
+        assert history.producer is None
+
+    @patch("generator._import_kafka")
+    def test_add_sends_to_kafka(self, mock_import):
+        """add отправляет сообщение в Kafka."""
+        mock_producer = MagicMock()
+        mock_producer_class = MagicMock(return_value=mock_producer)
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+        now = datetime.now(timezone.utc)
+        record = BatchRecord(
+            batch_id="test123",
+            started_at=now,
+            finished_at=now,
+            sent_total=100,
+            sent_browser=25,
+            sent_location=25,
+            sent_device=25,
+            sent_geo=25,
+            status="success",
+            error_message=None,
+        )
+
+        history.add(record)
+
+        mock_producer.send.assert_called_once()
+        call_args = mock_producer.send.call_args
+        assert call_args[0][0] == "generator_batch_history"
+        assert call_args[1]["key"] == "test123"
+        assert "value" in call_args[1]
+
+    @patch("generator._import_kafka")
+    def test_add_skips_if_not_initialized(self, mock_import):
+        """add пропускает если не инициализирован."""
+        mock_producer_class = MagicMock(side_effect=Exception("Connection failed"))
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+        now = datetime.now(timezone.utc)
+        record = BatchRecord(
+            batch_id="skip456",
+            started_at=now,
+            finished_at=now,
+            sent_total=0,
+            sent_browser=0,
+            sent_location=0,
+            sent_device=0,
+            sent_geo=0,
+            status="error",
+            error_message="Test",
+        )
+
+        # Не должно упасть
+        history.add(record)
+
+    @patch("generator._import_kafka")
+    def test_add_handles_send_error(self, mock_import):
+        """add обрабатывает ошибку отправки."""
+        mock_producer = MagicMock()
+        mock_producer.send.side_effect = Exception("Send failed")
+        mock_producer_class = MagicMock(return_value=mock_producer)
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+        now = datetime.now(timezone.utc)
+        record = BatchRecord(
+            batch_id="fail789",
+            started_at=now,
+            finished_at=now,
+            sent_total=50,
+            sent_browser=12,
+            sent_location=13,
+            sent_device=12,
+            sent_geo=13,
+            status="success",
+            error_message=None,
+        )
+
+        # Не должно упасть
+        history.add(record)
+
+    @patch("generator._import_kafka")
+    def test_flush_calls_producer_flush(self, mock_import):
+        """flush вызывает flush у producer."""
+        mock_producer = MagicMock()
+        mock_producer_class = MagicMock(return_value=mock_producer)
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+        history.flush()
+
+        mock_producer.flush.assert_called_once()
+
+    @patch("generator._import_kafka")
+    def test_flush_noop_if_not_initialized(self, mock_import):
+        """flush ничего не делает если не инициализирован."""
+        mock_producer_class = MagicMock(side_effect=Exception("Connection failed"))
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+        # Не должно упасть
+        history.flush()
+
+    @patch("generator._import_kafka")
+    def test_close_calls_producer_close(self, mock_import):
+        """close вызывает close у producer."""
+        mock_producer = MagicMock()
+        mock_producer_class = MagicMock(return_value=mock_producer)
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+        history.close()
+
+        mock_producer.close.assert_called_once()
+
+    @patch("generator._import_kafka")
+    def test_close_noop_if_not_initialized(self, mock_import):
+        """close ничего не делает если не инициализирован."""
+        mock_producer_class = MagicMock(side_effect=Exception("Connection failed"))
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+        # Не должно упасть
+        history.close()
+
+    @patch("generator._import_kafka")
+    def test_get_stats_returns_status(self, mock_import):
+        """get_stats возвращает статус инициализации."""
+        mock_producer_class = MagicMock()
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+        stats = history.get_stats()
+
+        assert stats["initialized"] is True
+        assert stats["topic"] == "generator_batch_history"
+
+    @patch("generator._import_kafka")
+    def test_get_stats_handles_not_initialized(self, mock_import):
+        """get_stats корректен при неинициализированном состоянии."""
+        mock_producer_class = MagicMock(side_effect=Exception("Connection failed"))
+        mock_import.return_value = (mock_producer_class, Exception)
+
+        history = KafkaBatchHistory("localhost:9092")
+        stats = history.get_stats()
+
+        assert stats["initialized"] is False
+        assert stats["topic"] == "generator_batch_history"