feat: Step1~Step14 面板单步按钮 EventBus 解耦 + Handler 补全（Step8~Step14）+ 旧上帝类删除

- 9 个面板（step1~step6/step8_ml_train/step8_qaa/step9_ml_predict/step10）单步执行按钮从 parent 链上溯改为 global_event_bus.publish('RequestRunSingleStep')

- PipelineExecutor 新增 _on_request_run_single_step 订阅

- 新增 Handler: step8_ml_train / step9_ml_predict / step10_qaa_inversion / step11_concentration / step12_kriging / step13_visualization / step14_report

- 删除旧 water_quality_inversion_pipeline_GUI.py（上帝类已肢解完毕）

src/gui/panels/step4_sampling_panel.py

@@ -91,7 +91,7 @@ class Step4SamplingPanel(QWidget):
         # 独立运行按钮
         self.run_btn = QPushButton("独立运行此步骤")
         self.run_btn.setStyleSheet(ModernStylesheet.get_button_stylesheet('success'))
-        self.run_btn.clicked.connect(self.run_step)
+        self.run_btn.clicked.connect(self._on_run_single_clicked)
         layout.addWidget(self.run_btn)
 
         # 交互式预览按钮
@@ -228,8 +228,23 @@ class Step4SamplingPanel(QWidget):
         # 4. 同步更新预览按钮状态（路径可能已自动填充）
         self._check_csv_exists()
 
+    def _on_run_single_clicked(self):
+        """通过 EventBus 发布单步执行请求（解耦面板与 PipelineExecutor）。"""
+        from src.gui.core.event_bus import global_event_bus
+
+        deglint_img_path = self.deglint_img_file.get_path()
+        if not deglint_img_path:
+            QMessageBox.warning(self, "输入错误", "请选择去耀斑影像文件！")
+            return
+
+        config = {'step4_sampling': self.get_config()}
+        global_event_bus.publish('RequestRunSingleStep', {
+            'step_name': 'step4_sampling',
+            'config': config,
+        })
+
     def run_step(self):
-        """独立运行步骤4"""
+        """独立运行步骤4（旧版 parent 链上溯方式，保留兼容）。"""
         deglint_img_path = self.deglint_img_file.get_path()
         if not deglint_img_path:
             QMessageBox.warning(self, "输入错误", "请选择去耀斑影像文件！")