fix: auto-fix code issues (cron)

- 修复重复导入/字段
- 修复异常处理
- 修复PEP8格式问题
- 添加类型注解

backend/test_phase8_task4.py

@@ -181,14 +181,14 @@ async def test_predictions(trend_model_id: str, anomaly_model_id: str) -> None:
     # 2. 趋势预测
     print("2. 趋势预测...")
     trend_result = await manager.predict(
-        trend_model_id, {"historical_values": [10, 12, 15, 14, 18, 20, 22]}
+        trend_model_id, {"historical_values": [10, 12, 15, 14, 18, 20, 22]},
     )
     print(f"   预测结果: {trend_result.prediction_data}")
 
     # 3. 异常检测
     print("3. 异常检测...")
     anomaly_result = await manager.predict(
-        anomaly_model_id, {"value": 50, "historical_values": [10, 12, 11, 13, 12, 14, 13]}
+        anomaly_model_id, {"value": 50, "historical_values": [10, 12, 11, 13, 12, 14, 13]},
     )
     print(f"   检测结果: {anomaly_result.prediction_data}")