fix(generator): исключено смешение миров при запуске

- Зачем:
  - старый state и ручной live-генератор могли тихо писать события в новый мир данных.
- Что:
  - добавлена общая проверка чистого стенда для Airflow и host-путей.
  - защищены backfill, import, continue и clean-start сценарии live-generator.
  - описан миграционный отказ старого state.
- Проверка:
  - make generator-test; docker compose config --quiet; py_compile; bash -n.

generator/src/clickstream_generator/kafka_io.py

@@ -9,6 +9,7 @@ from datetime import datetime
 
 from clickstream_generator.metrics import METRICS_ERRORS_TOTAL, METRICS_EVENTS_TOTAL
 from clickstream_generator.state import GeneratorState
+from clickstream_generator.state import UnsupportedStateVersionError
 
 
 logger = logging.getLogger("generator")
@@ -178,14 +179,24 @@ class KafkaStateManager:
                     f"Restored state: tick={last_state.get('tick')}, "
                     f"last_batch_id={last_state.get('last_batch_id')}"
                 )
-                restored = GeneratorState.from_dict_safe(last_state)
-                if restored is None:
+                try:
+                    restored = GeneratorState.from_dict(last_state)
+                except UnsupportedStateVersionError:
+                    logger.error(
+                        "Unsupported generator state version %s",
+                        last_state.get("version", "1.0"),
+                    )
+                    raise
+                except ValueError:
                     logger.warning("State data was invalid, starting fresh")
+                    return None
                 return restored
 
             logger.info("No previous state found, starting fresh")
             return None
 
+        except UnsupportedStateVersionError:
+            raise
         except Exception as e:
             logger.warning(f"Failed to load state: {e}, starting fresh")
             return None