feat(FileSelectWidget): 优化文件对话框初始目录为当前输入路径所在目录

src/gui/water_quality_gui.py

@@ -874,13 +874,23 @@ class FileSelectWidget(QWidget):
 
     def browse_file(self):
         """浏览文件"""
+        # 获取当前输入框中的文本，尝试从中提取初始目录
+        current_text = self.line_edit.text().strip()
+        initial_dir = ""
+        
+        if current_text:
+            # 尝试使用当前路径的目录作为初始目录
+            dir_path = os.path.dirname(current_text)
+            if dir_path and os.path.exists(dir_path):
+                initial_dir = dir_path
+        
         if self.mode == "save":
             file_path, _ = QFileDialog.getSaveFileName(
-                self, "保存文件", "", self.file_filter
+                self, "保存文件", initial_dir, self.file_filter
             )
         else:
             file_path, _ = QFileDialog.getOpenFileName(
-                self, "选择文件", "", self.file_filter
+                self, "选择文件", initial_dir, self.file_filter
             )
         if file_path:
             self.line_edit.setText(file_path)