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/sessions/create.rb

@@ -24,7 +24,9 @@ module Sessions
       )
 
       if session.platform == "youtube"
-        attach_youtube_broadcast!(session)
+        youtube_channel = @params[:youtube_channel].presence
+        assert_youtube_channel!(youtube_channel)
+        attach_youtube_broadcast!(session, youtube_channel: youtube_channel)
       end
 
       StreamSession.transaction do
@@ -39,8 +41,18 @@ module Sessions
 
     private
 
-    def attach_youtube_broadcast!(session)
-      yt = Youtube::BroadcastService.new(session.match.team)
+    def assert_youtube_channel!(youtube_channel)
+      resolver = Youtube::CredentialResolver.new(@match.team, channel: youtube_channel)
+      if resolver.resolve.blank?
+        raise Teams::EntitlementError.new(
+          "Canale YouTube selezionato non disponibile",
+          code: "youtube_channel_unavailable"
+        )
+      end
+    end
+
+    def attach_youtube_broadcast!(session, youtube_channel: nil)
+      yt = Youtube::BroadcastService.new(session.match.team, youtube_channel: youtube_channel)
       title = "#{session.match.team.name} vs #{session.match.opponent_name}"
       broadcast = yt.create_broadcast!(
         title: title,