EFV advanced segment disguise with real image properties, original-poster uploads, and VIP category restrictions

I worked overtime during Qingming Festival, also using development to improve my coding skills, and added advanced and practical features. The first major EFVCMS update is advanced segment disguise: segments become images with all image properties and can be used directly as images, replacing the old simple custom-extension setting. Second, original-poster uploads retain the image's dimensions rather than cropping, storing width and height in the database; this also suits animated posters. Third, download deletion was rewritten with batch task deletion. Fourth, added a fast-slicing-failure filter. Fifth, VIP groups can restrict full playback of a category to a designated VIP group. Create an Advanced VIP Area category and assign it to your highest VIP group as an exclusive category, so only the highest VIP group watches that area, the advanced VIP area. Sixth, preview logic was rewritten for better speed and efficiency.

Updates

1. Advanced segment disguise gives segments all image properties, usable directly as images. Removed custom extensions; see details below.
2. Added original-image uploads without cropping for poster 2, with dimensions stored in the database, including animated gif images.
3. Rewrote download-center deletion and added batch deletion.
4. Added fast-slicing failures to transcoding-status filters.
5. Advanced VIP groups can access selected exclusive categories, limiting a category to a designated VIP group.
6. Rewrote preview logic for speed and efficiency.
7. Minor BUG fixes and feature refinements.

Segment disguise

Disguised segments are now PNG images.

Compatibility has been specifically improved for all browsers, including UC, QQ, Quark, oppo and Apple IOS.

A disguised m3u8 cannot be assembled directly in some cases, and an assembled file may still not play. More sophisticated download-and-assembly tools may nevertheless exist.