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/utils.py

@@ -24,7 +24,7 @@ class RealtimeOutput:
         """写入文本"""
         if text:
             # 将文本按行分割，逐行回调
-            lines = text.split('\n')
+            lines = text.split("\n")
             for line in lines:
                 if line:  # 忽略空行（由 split 产生）
                     self.callback(line)