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/services/mediamtx/publisher_online.rb

@@ -0,0 +1,37 @@
+module Mediamtx
+  # Telefono connesso al path RTMP (non solo slate alwaysAvailable).
+  module PublisherOnline
+    module_function
+
+    def active?(session)
+      active_path?(path_info(session))
+    end
+
+    def path_info(session)
+      Client.new.list_paths.find { |i| i["name"] == session.mediamtx_path_name }
+    end
+
+    def active_path?(info)
+      return false unless info
+
+      info["online"] == true && info.dig("source", "type") == "rtmpConn"
+    end
+
+    def h264_video?(info)
+      return false unless info
+
+      (info["tracks2"] || []).any? do |track|
+        track["codec"] == "H264" && track.dig("codecProps", "width").to_i.positive?
+      end
+    end
+
+    def video_publishing?(session)
+      info = path_info(session)
+      return false unless active_path?(info)
+      # Slate alwaysAvailable ha H264 ma non è il telefono.
+      return false unless info.dig("source", "type") == "rtmpConn"
+
+      h264_video?(info)
+    end
+  end
+end