feat: update requirements and enhance task guide UI

- Added core dependencies for file handling (Pillow, openpyxl, python-docx, PyPDF2, chardet) to requirements.txt.
- Modified SandboxRunner to create a dedicated codes directory for task scripts.
- Expanded prompts.py with a list of allowed libraries for code generation.
- Simplified the task guide UI by removing drag-and-drop functionality and enhancing layout and styling for better user experience.

.gitignore

@@ -0,0 +1,38 @@
+# Python 编译缓存
+__pycache__/
+*.py[cod]
+*$py.class
+*.pyo
+*.pyd
+
+# 虚拟环境
+.env
+.venv/
+env/
+venv/
+ENV/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# 工作区（运行时生成的文件）
+workspace/
+
+# 系统文件
+.DS_Store
+Thumbs.db
+desktop.ini
+
+# 日志
+*.log
+
+# 打包
+dist/
+build/
+*.egg-info/
+*.spec
+