Support wildcard types e.g. `image/*`

It would be very useful to be able to say "any kind of image is fine" with e.g. `image/*` as an allowed type, rather than having to list out every specific image format you want to expect.

For responsibility it should be documented as to be considered carefully, as e.g. `image/*` feels harmless as it's just image formats, but that includes `image/svg+xml` which can carry risks via XML external entity attacks, CSS exfiltration using fonts, scripts etc - so not just "an image"!)

To go along with it, it would probably also be useful to be able to negate MIME types, so you could say "all images, except..." e.g. `image/* !image/svg+xml` or similar so that it's possible to skip particular ones you're worried about without having to go back to listing out every other acceptable type.

issue 中没有指明文件或测试。首先定位 plugin 现有的允许 MIME 类型验证及其测试；当通配符和否定的 MIME 类型按约定运行，并且安全文档涵盖 SVG 及相关风险时，即视为完成。

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