Add tests for clipboard image functionality and mesh plane asset creation

- Implemented a comprehensive test suite for the clipboard image module, covering various functionalities including operator registration, context handling, and image processing.
- Created a new mesh plane asset with customizable parameters and integrated it into the geometry node system.
- Developed a validation script to ensure the correct behavior of the mesh plane asset, including input handling and output verification.

mkdocs.yml

@@ -12,8 +12,10 @@ nav:
   - 开始使用:
       - 安装与首次配置: installation.md
       - 五分钟上手: quick-start.md
+      - 粘贴剪贴板图片: clipboard-image.md
   - 使用指南:
       - 选择转换方式: workflows.md
+      - Mesh Plane: mesh-plane.md
       - Depth Plane: guide-depth-plane.md
       - Surface: guide-surface.md
       - 去除背景: remove-background.md