fix(step12_viz): scatter 模型目录改读 self.extra + 主线程 step8 预取注入

worker generate_all_selected.gen_scatter 块改读 self.extra['models_dir']，

fallback 到 wp / 8_Supervised_Model_Training（替换旧版 7_Supervised_Model_Training）。

主线程 generate_all_visualizations 通过 panel_factory.get_panel('step8_ml_train')

预取 step8 panel.output_path，注入 extra 字典 models_dir 键。

Why: 子线程内 self.window() 无意义（VisualizationWorkerThread 是 QThread 子类

且无 parent 传参），必须主线程预取 + worker 读 extra 字典。与同文件既有

scatter 任务（line 208-209）和 step11 风格统一。

src/gui/panels/step12_viz_panel.py

@@ -223,11 +223,19 @@ class VisualizationWorkerThread(QThread):
                 viz = WaterQualityVisualization(output_dir=str(resolve_subdir(self.work_dir, 'visualization')))
                 parts = []
 
-                training_csv = wp / "5_training_spectra" / "training_spectra.csv"
+                training_csv_path = (self.extra.get("training_csv_path") or "").strip()
+                if training_csv_path:
+                    training_csv = Path(training_csv_path)
+                else:
+                    training_csv = wp / "5_training_spectra" / "training_spectra.csv"
 
                 if self.extra.get("gen_scatter"):
                     if training_csv.is_file():
-                        models_dir = wp / "7_Supervised_Model_Training"
+                        models_dir_str = (self.extra.get("models_dir") or "").strip()
+                        if models_dir_str:
+                            models_dir = Path(models_dir_str)
+                        else:
+                            models_dir = wp / "8_Supervised_Model_Training"
                         if models_dir.is_dir() and any(d.is_dir() for d in models_dir.iterdir()):
                             from src.core.visualization.scatter_plot import generate_model_scatter_plots
                             scatter_paths = generate_model_scatter_plots(
@@ -1672,6 +1680,18 @@ class Step12VizPanel(QWidget):
             "gen_mask_glint": self.gen_mask_glint.isChecked(),
             "gen_sampling_map": self.gen_sampling_map.isChecked(),
         }
+        main_window = self.window()
+        factory = getattr(main_window, '_panel_factory', None) if main_window else None
+        step5_panel = factory.get_panel('step5_clean') if factory else None
+        if step5_panel and getattr(step5_panel, 'output_file', None):
+            _resolved_csv = step5_panel.output_file.get_path()
+            if _resolved_csv:
+                extra["training_csv_path"] = _resolved_csv
+        step8_panel = factory.get_panel('step8_ml_train') if factory else None
+        if step8_panel and getattr(step8_panel, 'output_path', None):
+            _resolved_models_dir = step8_panel.output_path.get_path()
+            if _resolved_models_dir:
+                extra["models_dir"] = _resolved_models_dir
         self._start_visualization_thread("generate_all_selected", extra)
 
     def generate_chart(self, chart_type):
@@ -1684,7 +1704,13 @@ class Step12VizPanel(QWidget):
             QMessageBox.warning(self, "警告", "工作目录不存在！")
             return
         try:
-            training_spectra_csv = _viz_training_spectra_csv_path(work_path)
+            main_window = self.window()
+            factory = getattr(main_window, '_panel_factory', None) if main_window else None
+            step5_panel = factory.get_panel('step5_clean') if factory else None
+            if step5_panel and getattr(step5_panel, 'output_file', None) and step5_panel.output_file.get_path():
+                training_spectra_csv = Path(step5_panel.output_file.get_path())
+            else:
+                training_spectra_csv = _viz_training_spectra_csv_path(work_path)
             if chart_type == 'scatter':
                 if not training_spectra_csv.is_file():
                     QMessageBox.warning(