refactor(pipeline): step8 输出文件命名统一为 training_spectra_indices.csv，produces 增加 trad_indices_dir

src/core/pipeline/runner.py

@@ -116,10 +116,10 @@ PIPELINE_STEPS: List[StepSpec] = [
     ),
     StepSpec(
         step_id="step8", method_name="step8_water_quality_indices",
-        requires=["training_csv_path"], produces=["indices_path"],
+        requires=["training_csv_path"], produces=["indices_path", "trad_indices_dir"],
         required_input_files=["training_csv_path"],
-        output_file="{work_dir}/6_water_quality_indices/water_quality_indices.csv",
-        description="水质光谱指数计算（optional）",
+        output_file="{work_dir}/6_water_quality_indices/training_spectra_indices.csv",
+        description="水质光谱指数计算（双轨输出：A轨宽表 + B轨单文件）",
     ),
     StepSpec(
         step_id="step7", method_name="step7_ml_modeling",

src/core/steps/data_preparation_step.py

@@ -161,7 +161,7 @@ class DataPreparationStep:
         if output_file:
             output_path = str(Path(output_file))
         else:
-            output_path = str(output_dir / "water_quality_indices.csv")
+            output_path = str(output_dir / "training_spectra_indices.csv")
 
         if Path(output_path).exists():
             print(f"检测到已存在的水质指数文件，直接使用: {output_path}")