Stabilizza live YouTube/RTMP e fix crash rotazione mobile.

Pipeline YouTube con relay, overlay e publisher sync lato backend; fix GL pauseGlDuringRotation su Android per evitare crash in rotazione durante lo streaming Flutter.

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

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

@@ -56,6 +56,7 @@ module Api
           fps: params[:fps],
           last_seen_at: Time.current
         )
+        sync_publisher_when_streaming!(params[:fps].to_f)
         SessionChannel.broadcast_message(@session, state.as_cable_payload)
         head :no_content
       end
@@ -172,6 +173,19 @@ module Api
           occurred_at: event.occurred_at
         }
       end
+
+      # L'app invia fps ogni ~10s; senza poll status.json l'overlay YouTube non partiva.
+      def sync_publisher_when_streaming!(fps)
+        return if fps < 1
+        return if @session.terminal? || @session.paused?
+        return unless @session.platform == "youtube"
+        return unless @session.status.in?(%w[connecting live reconnecting])
+
+        Mediamtx::PublisherSync.new(@session).call
+        if @session.platform == "youtube" && @session.status.in?(%w[live connecting reconnecting])
+          Mediamtx::PublisherSync.schedule_youtube_pipeline!(@session, force: false)
+        end
+      end
     end
   end
 end