feat: add extraction_service (PDF/Docx/Txt) and update .gitignore to exclude venv

extraction_service/.gitignore

@@ -0,0 +1,40 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+env/
+venv/
+ENV/
+build/
+dist/
+*.egg-info/
+
+# 环境变量
+.env
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# 临时文件
+/tmp/
+*.log
+
+# 测试
+.pytest_cache/
+.coverage
+htmlcov/
+
+# OS
+.DS_Store
+Thumbs.db
+
+
+
+
+
+