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/streams/cover_slate_ensurer.rb

@@ -0,0 +1,35 @@
+module Streams
+  # Garantisce che la slate MP4 esista per il record effettivo della partita (sync al go-live).
+  class CoverSlateEnsurer
+    def self.ensure_for!(match)
+      new(match).ensure!
+    end
+
+    def initialize(match)
+      @match = match
+      @resolver = CoverResolver.new(match)
+    end
+
+    def ensure!
+      result = @resolver.resolve
+      return unless result
+
+      record = result.record
+      return if slate_ready?(record)
+
+      GenerateCoverSlate.call(record)
+    rescue GenerateCoverSlate::Error => e
+      Rails.logger.warn("[CoverSlateEnsurer] match=#{@match.id} #{e.message}")
+      nil
+    end
+
+    private
+
+    def slate_ready?(record)
+      return false unless record.cover_slate.attached?
+
+      path = CoverSlatePaths.local_path_for(record)
+      path.present? && File.exist?(path)
+    end
+  end
+end