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/spec/requests/api/v1/sports_spec.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe "Api::V1::Sports", type: :request do
+  let!(:user) { User.create!(email: "s@example.com", password: "secret123", name: "U", role: "coach") }
+
+  it "GET /api/v1/sports restituisce il catalogo" do
+    post "/api/v1/auth/login", params: { email: user.email, password: "secret123" }
+    token = response.parsed_body["access_token"]
+    get "/api/v1/sports", headers: { "Authorization" => "Bearer #{token}" }
+    expect(response).to have_http_status(:ok)
+    body = JSON.parse(response.body)
+    expect(body).to be_an(Array)
+    pallavolo = body.find { |s| s["key"] == "pallavolo" }
+    expect(pallavolo["board"]).to eq("volley")
+    expect(pallavolo["allowed_overlays"]).to include("volley", "timer", "none")
+  end
+end