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/services/youtube/broadcast_service.rb

@@ -2,9 +2,9 @@ module Youtube
   class BroadcastService
     class Error < StandardError; end
 
-    def initialize(team)
+    def initialize(team, youtube_channel: nil)
       @team = team
-      @resolver = CredentialResolver.new(team)
+      @resolver = CredentialResolver.new(team, channel: youtube_channel)
       @credential = @resolver.resolve
     end