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/step14_panel.py

@@ -27,12 +27,7 @@ from PyQt5.QtWidgets import (
 from src.gui.components.custom_widgets import FileSelectWidget
 from src.gui.styles import ModernStylesheet
 
-# Pipeline 可用性（与 core/worker_thread.py 保持一致）
-try:
-    from src.core.water_quality_inversion_pipeline_GUI import WaterQualityInversionPipeline
-    PIPELINE_AVAILABLE = True
-except ImportError:
-    PIPELINE_AVAILABLE = False
+PIPELINE_AVAILABLE = True
 
 
 class Step14BatchThread(QThread):
@@ -63,19 +58,19 @@ class Step14BatchThread(QThread):
         except Exception:
             mpl_prev = None
         try:
-            from src.core.water_quality_inversion_pipeline_GUI import WaterQualityInversionPipeline
-            pipeline = WaterQualityInversionPipeline(work_dir=self.work_dir)
+            from src.core.steps.mapping_step import MappingStep
             n = len(self.csv_paths)
             for i, csv_p in enumerate(self.csv_paths):
                 self.progress.emit(i + 1, n)
                 self.log_message.emit(f"专题图 [{i + 1}/{n}] {csv_p}", "info")
-                kw = {**self.step14_kwargs, "prediction_csv_path": csv_p, "skip_dependency_check": True}
+                kw = {**self.step14_kwargs, "prediction_csv_path": csv_p}
+                kw.pop("skip_dependency_check", None)
                 if self.output_dir_optional:
                     stem = Path(csv_p).stem
                     kw["output_image_path"] = str(Path(self.output_dir_optional) / f"{stem}_distribution.png")
                 else:
                     kw["output_image_path"] = None
-                pipeline.step10_map(**kw)
+                MappingStep.generate_distribution_map(**kw)
             self.finished_ok.emit(n)
         except Exception as e:
             self.failed.emit(f"{e}\n{traceback.format_exc()}")