Billing upgrade/downgrade, inviti in app e diretta YouTube da mobile.

Upgrade Stripe con addebito immediato; downgrade programmato a fine periodo.
UX billing più sobria con box info; icone piani. API inviti e OAuth YouTube
per staff trasmissione; deep link join; scelta partita programmata o nuova.

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

backend/app/controllers/public/teams_controller.rb

@@ -116,7 +116,7 @@ module Public
     end
 
     def youtube_connect
-      require_club_owner_for_team!(@team)
+      require_youtube_connect_access!(@team)
       @team.entitlements.assert_can_connect_youtube!
 
       if ENV["YOUTUBE_CLIENT_ID"].blank?
@@ -124,7 +124,12 @@ module Public
         return
       end
 
-      state = Youtube::OauthState.for_team(team_id: @team.id, user_id: current_user.id)
+      return_app = params[:return_app] == "1"
+      state = Youtube::OauthState.for_team(
+        team_id: @team.id,
+        user_id: current_user.id,
+        return_app: return_app
+      )
       redirect_to Youtube::OauthUrl.build(state: state), allow_other_host: true
     rescue Teams::EntitlementError => e
       redirect_to public_team_details_path(@team), alert: e.message
@@ -138,6 +143,13 @@ module Public
 
     private
 
+    def require_youtube_connect_access!(team)
+      return if team.club&.owned_by?(current_user)
+      return if current_user.can_stream_for?(team)
+
+      redirect_to public_team_details_path(team), alert: "Accesso non consentito"
+    end
+
     def load_team_details!
       @club = @team.club
       @can_manage = @club.owned_by?(current_user)