Introduce architettura multi-sport con catalogo, engine scoring e overlay.

Catalogo sport in YAML, board implicito, engine per volley/basket/timed/racket/timer/generic, regia e app Android allineate.

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

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

@@ -0,0 +1,9 @@
+module Api
+  module V1
+    class SportsController < BaseController
+      def index
+        render json: Sports::Catalog.as_api_list
+      end
+    end
+  end
+end