Fix YouTube in attesa: audio AAC di riserva, retry attivazione broadcast

Il relay verso YouTube ora gestisce _air senza traccia audio, ritenta
activate_broadcast finché l'ingest è active e riduce la finestra
scheduledStartTime a ~20s.

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

backend/app/jobs/youtube_broadcast_activate_job.rb

@@ -1,13 +1,27 @@
 class YoutubeBroadcastActivateJob < ApplicationJob
   queue_as :default
 
-  def perform(session_id)
+  MAX_ATTEMPTS = 36
+  RETRY_WAIT = 10.seconds
+  class << self
+    def schedule_with_retries(session_id, attempt: 1)
+      set(wait: attempt == 1 ? 8.seconds : RETRY_WAIT).perform_later(session_id, attempt)
+    end
+  end
+
+  def perform(session_id, attempt = 1)
     session = StreamSession.find_by(id: session_id)
     return unless session&.platform == "youtube"
     return if session.terminal?
     return if session.youtube_broadcast_id.blank?
     return unless Streams::YoutubeRelay.running?(session.id)
 
-    Youtube::BroadcastService.new(session.match.team).activate_broadcast!(session.youtube_broadcast_id)
+    result = Youtube::BroadcastService.new(session.match.team).activate_broadcast!(session.youtube_broadcast_id)
+    return if result == :live || result == :transitioned
+
+    return unless result == :waiting_ingest
+    return if attempt >= MAX_ATTEMPTS
+
+    self.class.schedule_with_retries(session_id, attempt: attempt + 1)
   end
 end