pik-bridge — PikPak 直链 → 光鸭 离线下载中转

A. 直通(无需KV):  /d/<filename.ext>?u=<urlencoded 源URL>
B. KV短链:        /f/<token>/<filename.ext>   (需绑定 LINKS)
   POST /admin/put  {url,filename,contentType?,token?,ttl?}  ->  {token,feedUrl}

allowed hosts: mypikpak.com, pikpak.com, mypikpak.net