fix(06-03): remove sys.path manipulation from zhihu_metadata.py

- Remove unnecessary sys.path.insert for current directory
- Use relative import for zhihu_extractor
- Package imports work correctly without path manipulation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

kb_workflow/metadata/zhihu_metadata.py

@@ -15,12 +15,7 @@ import sys
 import os
 from typing import Dict, Optional, Any
 
-# 添加当前目录到 Python 路径
-current_dir = os.path.dirname(os.path.abspath(__file__))
-if current_dir not in sys.path:
-    sys.path.insert(0, current_dir)
-
-from zhihu_extractor import ZhihuPlaywrightExtractor
+from .zhihu_extractor import ZhihuPlaywrightExtractor
 
 
 def extract_zvideo(video_id: str, headless: bool = True, cookie: str = None) -> Dict[str, Any]: