Add comprehensive tests for image processing and mask functionalities

- Introduced tests for color image handling, ensuring source preservation and premultiplied alpha usage.
- Implemented tests for brush stroke operations, validating segment boundaries and brush anti-aliasing.
- Added tests for frame anti-aliasing, confirming correct rendering behavior with various alpha values and depth settings.
- Created tests for frame projection, ensuring accurate overlap calculations and half-plane clipping.
- Developed tests for image premultiplied retention, verifying behavior during loading and packing processes.
- Added undo functionality tests for mask operations, ensuring single transaction behavior during edits.

docs/internals/operators/index.md

@@ -9,7 +9,7 @@
 | `operators/clipboard_image/` | [Clipboard Image](clipboard-image.md) | 系统剪贴板读取、粘贴与快捷键 |
 | `operators/convert_to_plane/` | [Convert to Plane](convert-to-plane.md) | Mesh Plane 与 Depth Plane 创建 |
 | `operators/cutout_tool/` | [Cutout Tool](cutout-tool.md) | Selection、基础 Shape 构建与 Blender 对象创建 |
-| `operators/crop_tool/` | [Crop Tool](crop-tool.md) | Box、Lasso、Polyline 与 Perspective 图片裁切 |
+| `operators/image_edit_tool/` | [Image Edit Tool](image-edit-tool.md) | Frame 合成、Mask Alpha 编辑与 Rectify 透视校正 |
 | `operators/debug.py` | [Debug Operator](debug.md) | 模型接口与原始产物验证 |
 | `operators/remove_background.py` | [Remove Background](remove-background.md) | BEN2 去背与结果替换 |
 | `operators/upscale.py` | [Upscale](upscale.md) | 当前 Image 的 4× 高清与输入长边检查 |