Closes: [BS-3586](https://linear.app/affine-design/issue/BS-3586/复制白板图片，然后粘贴到-page，图片失败)
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Copying a single selected image in edgeless mode now places the image directly onto the system clipboard as a native image blob for smoother pasting.
- **Bug Fixes**
- Enhanced clipboard handling to better manage image and text data inclusion, with improved fallback for snapshot HTML.
- **Tests**
- Added an end-to-end test verifying image copy-paste functionality between edgeless and page editor modes.
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fundon