Aggiunge overlay server-side burn-in e stabilizza diretta live.

Tabellone, badge e brand sono ricodificati nel flusso _air via OverlayRelay;
sync punteggio HTTP, volume condiviso rails/sidekiq, qualità 720p migliorata
e badge CONNECTING in ripresa da pausa.

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

backend/app/services/sessions/pause.rb

@@ -7,10 +7,11 @@ module Sessions
     def call
       cancel_timeout_job
       @session.pause! if @session.may_pause?
-      ensure_slate_on_path
+      # Slate già su path (create_path + alwaysAvailable): stop RTMP basta, senza patch API.
       log_event("paused")
       SessionChannel.broadcast_message(@session, { type: "command", action: "pause_stream" })
       SessionChannel.broadcast_message(@session, { type: "stream_event", event: "paused" })
+      Streams::Overlay::Refresh.call(@session)
       @session
     end
 
@@ -23,12 +24,6 @@ module Sessions
       @session.update!(timeout_job_id: nil)
     end
 
-    def ensure_slate_on_path
-      Mediamtx::Client.new.patch_path(@session)
-    rescue Mediamtx::Client::Error => e
-      Rails.logger.warn("[Sessions::Pause] slate path patch failed: #{e.message}")
-    end
-
     def log_event(type)
       @session.stream_events.create!(event_type: type, occurred_at: Time.current, metadata: {})
     end