fix(step7): 消除UnboundLocalError — 将Path/os导入上移至函数第一行，避免与后续局部赋值冲突

src/core/steps/prediction_step.py

@@ -28,6 +28,7 @@ class PredictionStep:
         callback: Optional[Callable] = None,
     ) -> str:
         """生成水域掩膜内且耀斑掩膜外的采样点，统计平均光谱"""
+        from pathlib import Path
         from src.utils.sampling import get_spectral_sampling_points_chunked
 
         output_dir = Path(output_dir)
@@ -47,9 +48,6 @@ class PredictionStep:
         if deglint_img_path is None:
             raise ValueError("必须提供 deglint_img_path 参数")
 
-        from pathlib import Path
-        import os
-
         # 1. 初始归一化与安全转换
         original_path = Path(deglint_img_path)
         final_deglint_path = original_path