pdf 压缩/合并/文字提取: https://kitt.tools/files/pdf
来自 https://github.com/J-F-Liu/lopdf
图片/音频信息隐写: https://kitt.tools/fun/steganography
来自 https://github.com/steganogram/stegano-rs
图像转 svg(主要用于生成无损图): https://kitt.tools/fun/visioncortex
来自 https://github.com/visioncortex/vtracer
