Promotion system rewritten with personal dashboards and automatic revenue sharing; subtitle-extraction transcoding BUG fixed

This update mainly rewrites the promotion system in the built-in CMS. It may later be ported to the APP. We also fixed a BUG where subtitle-stream export left videos stuck in fast slicing or transcoding.

Changelog

1. Fixed a transcoding BUG when only a single fullscreen moving image watermark is present.
2. Fixed an intermittent BUG where extracting embedded subtitles from mkv and other formats left processing stuck in transcoding or fast slicing.
3. Completely rewrote promotion in the built-in CMS. Successfully referred users remain permanently associated with their referrer, who immediately earns a configured commission when they top up.

Promotion workflow

A user shares their referral link -> a visitor opens it, with attribution valid for 30 days -> registers -> becomes associated with the referrer -> completes a transaction -> the configured revenue share is converted to points and credited to the promoter's account.

Removed the previous point-award mechanism for visits through referral links because it was easy to manipulate, and removed its point settings. Added revenue-share percentage settings, a personal promotion dashboard, referrer display on orders and a promotion-record center showing referred registrations and their referrers.

Screenshots