Implementa pausa diretta con copertina slate e ripresa.

Metti in pausa ferma RTMP lato app mantenendo la camera aperta, MediaMTX
manda offline.mp4 agli spettatori e Chiudi termina definitivamente.

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

backend/app/services/sessions/pause.rb

@@ -5,14 +5,30 @@ module Sessions
     end
 
     def call
+      cancel_timeout_job
       @session.pause! if @session.may_pause?
+      ensure_slate_on_path
       log_event("paused")
       SessionChannel.broadcast_message(@session, { type: "command", action: "pause_stream" })
+      SessionChannel.broadcast_message(@session, { type: "stream_event", event: "paused" })
       @session
     end
 
     private
 
+    def cancel_timeout_job
+      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 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