App: scelta canale YouTube MLTV/società, privacy e condivisione link.

Premium Full può forzare il canale piattaforma; visibilità non in elenco o privato;
share_url unificato per Match Live TV e YouTube.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/controllers/api/v1/stream_sessions_controller.rb

@@ -118,7 +118,7 @@ module Api
       end
 
       def session_params
-        params.permit(:platform, :privacy_status, :quality_preset, :target_bitrate, :target_fps)
+        params.permit(:platform, :privacy_status, :quality_preset, :target_bitrate, :target_fps, :youtube_channel)
       end
 
       def session_json(session, detail: false)
@@ -130,6 +130,8 @@ module Api
           rtmp_ingest_url: session.rtmp_ingest_url,
           hls_playback_url: session.hls_playback_url,
           watch_page_url: session.watch_page_url,
+          share_url: session.share_url,
+          youtube_watch_url: session.youtube_watch_url,
           youtube_broadcast_id: session.youtube_broadcast_id,
           privacy_status: session.privacy_status,
           quality_preset: session.quality_preset,