Corregge OAuth YouTube piattaforma senza access token in memoria.

Il refresh token ENV non veniva scambiato finché expires_at era vuoto,
causando 500 Unauthorized alla creazione sessione YouTube.

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

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

@@ -2,9 +2,17 @@ module Api
   module V1
     class BaseController < ApplicationController
       rescue_from Teams::EntitlementError, with: :render_entitlement_error
+      rescue_from Youtube::BroadcastService::Error, with: :render_youtube_error
 
       private
 
+      def render_youtube_error(error)
+        render json: {
+          error: "YouTube: #{error.message}",
+          error_code: "youtube_api_error"
+        }, status: :unprocessable_entity
+      end
+
       def render_entitlement_error(error)
         render json: {
           error: error.message,