style: normalize code formatting across the codebase

- Standardize quote style (single to double quotes)
- Improve code formatting consistency
- Apply formatting to utilities, GUI components, and tools
- Update imports and docstrings for consistency

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

gui/config_manager.py

@@ -58,7 +58,7 @@ class ConfigManager:
         Returns:
             配置值
         """
-        keys = key.split('.')
+        keys = key.split(".")
         value = self.config
 
         try:
@@ -78,7 +78,7 @@ class ConfigManager:
             key: 配置键
             value: 配置值
         """
-        keys = key.split('.')
+        keys = key.split(".")
         obj = self.config
 
         # 导航到父对象