feat: torrent streaming with hls transcoding (#1)

* feat: add ffmpeg for hls streaming

* feat: torrent streaming with hls transcoding

- add nyaa.si torrent search client
- add streaming service using anacrolix/torrent
- add hls transcoding via ffmpeg for browser playback
- add watch page with episode selection
- add socks5 proxy support via TORRENT_PROXY env
- switch to modernc.org/sqlite (pure go, no cgo conflicts)
- update dockerfile with ffmpeg

migrations/004_add_torrent_fields.sql

@@ -0,0 +1,3 @@
+-- name: AddAnimeTorrentFields :exec
+ALTER TABLE anime ADD COLUMN magnet_link TEXT;
+ALTER TABLE anime ADD COLUMN torrent_hash TEXT;