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/services/scoring/engine.rb

@@ -0,0 +1,26 @@
+module Scoring
+  class Engine
+    ENGINES = {
+      "volley" => Engines::VolleyEngine,
+      "racket" => Engines::RacketEngine,
+      "generic" => Engines::GenericEngine,
+      "basket" => Engines::BasketEngine,
+      "timed" => Engines::TimedEngine,
+      "timer" => Engines::TimerEngine
+    }.freeze
+
+    def self.for(match)
+      board = match.effective_board_type
+      klass = ENGINES.fetch(board) { Engines::GenericEngine }
+      klass.new(match: match)
+    end
+
+    def self.for_session(session)
+      for(session.match)
+    end
+
+    def self.ensure_score_for(session)
+      for(session.match).ensure_score(session)
+    end
+  end
+end