fix: resolve RealtimeOutput import error by moving to utils package

Python prefers packages over modules, causing imports to resolve to
gui/utils/__init__.py instead of gui/utils.py. Moved RealtimeOutput
class into the utils package to fix the ImportError.

Co-Authored-By: Claude (glm-5) <noreply@anthropic.com>

gui/utils/realtime_output.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+实时输出流模块
+"""
+
+
+class RealtimeOutput:
+    """实时输出流，每次写入立即回调通知"""
+
+    def __init__(self, callback):
+        """
+        初始化实时输出流
+
+        Args:
+            callback: 写入时的回调函数，接收文本内容
+        """
+        self.callback = callback
+        self.buffer = []
+
+    def write(self, text):
+        """写入文本"""
+        if text:
+            # 将文本按行分割，逐行回调
+            lines = text.split("\n")
+            for line in lines:
+                if line:  # 忽略空行（由 split 产生）
+                    self.callback(line)
+        return len(text)
+
+    def flush(self):
+        """刷新（兼容性方法）"""
+        pass
+
+    def isatty(self):
+        """返回 False，表示不是终端"""
+        return False