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/mediamtx/publisher_sync.rb

@@ -0,0 +1,51 @@
+module Mediamtx
+  # MediaMTX in produzione è distroless: runOnReady con wget non funziona.
+  # Sincronizziamo lo stato Rails leggendo l'API paths (poll da /live/:id/status.json).
+  class PublisherSync
+    def initialize(session)
+      @session = session
+    end
+
+    def call
+      return @session if @session.terminal?
+
+      info = Mediamtx::Client.new.list_paths.find { |i| i["name"] == @session.mediamtx_path_name }
+      publisher_online = info && info["online"]
+
+      if publisher_online
+        if @session.paused?
+          # RTMP ancora connesso in pausa: non forzare live/reconnect.
+        elsif @session.may_go_live?
+          @session.go_live!
+          Streams::Overlay::Refresh.call(@session.reload)
+        elsif @session.reconnecting? && @session.may_reconnect?
+          @session.reconnect!
+          cancel_timeout
+          Streams::Overlay::Refresh.call(@session.reload)
+        end
+      elsif !@session.paused? && @session.live? && @session.may_lose_connection?
+        @session.lose_connection!
+        schedule_timeout unless @session.paused?
+      end
+
+      @session.reload
+    end
+
+    private
+
+    def cancel_timeout
+      return if @session.timeout_job_id.blank?
+
+      Sidekiq::ScheduledSet.new.find_job(@session.timeout_job_id)&.delete
+      @session.update!(timeout_job_id: nil)
+    end
+
+    def schedule_timeout
+      job = DisconnectionTimeoutJob.perform_in(
+        MatchLiveTv.reconnect_timeout_seconds.seconds,
+        @session.id
+      )
+      @session.update!(timeout_job_id: job)
+    end
+  end
+end