Permette titolo, testo e link diversi per Android e iOS negli avvisi.

Separa i canali app e mostra il nodo ingest nelle sessioni admin.

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

backend/app/controllers/api/v1/announcements_controller.rb

@@ -5,7 +5,7 @@ module Api
 
       def index
         platform = params[:platform].to_s.presence
-        announcements = AppAnnouncement.for_app.newest
+        announcements = AppAnnouncement.for_platform(platform).newest
         render json: announcements.map { |item| item.as_api_json(platform: platform) }
       end
     end