Add fullporner provider with xiaoshenke proxy

- Implement fullporner.com provider with search, pagination, categories, pornstars
- Add xiaoshenke.net proxy for Cloudflare-protected embed videos
- Proxy fetches signed URLs via FlareSolverr and streams video content
- Fix quality bitmask mapping (1=360p, 2=480p, 4=720p, 8=1080p)
- Support HEAD/GET/Range for video streaming

Co-Authored-By: Claude Code <noreply@anthropic.com>

src/proxies/mod.rs

@@ -49,6 +49,7 @@ pub mod tube8;
 pub mod thepornbunny;
 pub mod vidara;
 pub mod vjav;
+pub mod xiaoshenke;
 
 #[derive(Debug, Clone)]
 pub enum AnyProxy {