Aggiunge copertina sponsor custom solo Premium Full, con override in wizard e slate sui nodi di streaming.

Permette upload da portale e app con ereditarietà partita→squadra→società, generazione MP4 via ffmpeg e distribuzione su home lab e nodi CPX per pause e assenza segnale.

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

backend/app/services/mediamtx/client.rb

@@ -28,7 +28,7 @@ module Mediamtx
         overridePublisher: true
       )
       body[:alwaysAvailable] = true
-      body[:alwaysAvailableFile] = slate_file_path
+      body[:alwaysAvailableFile] = slate_file_path(session)
       # YouTube: telefono → MediaMTX; relay copy verso RTMPS in sidekiq.
       response = @conn.post("/v3/config/paths/add/#{CGI.escape(path)}", body)
       unless response.success?
@@ -81,7 +81,7 @@ module Mediamtx
       return true if always_available_remembered?(path, enabled: enabled)
 
       body = if enabled
-               { alwaysAvailable: true, alwaysAvailableFile: slate_file_path }
+               { alwaysAvailable: true, alwaysAvailableFile: slate_file_path(session) }
              else
                { alwaysAvailable: false }
              end
@@ -173,7 +173,13 @@ module Mediamtx
       SCRIPT
     end
 
-    def slate_file_path
+    def slate_file_path(session)
+      return default_slate_file_path if session.blank?
+
+      Streams::SlateDistributor.slate_path_for_session(session)
+    end
+
+    def default_slate_file_path
       ENV.fetch("MEDIAMTX_SLATE_FILE", "/slates/offline.mp4")
     end