Billing Stripe, link regia mobile e staff solo trasmissione.

Aggiunge fatturazione club, pagina regia condivisibile senza account, roster squadre e rimuove la modalità controller dall'app (v1.1.0).

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

backend/spec/helpers/public/billing_helper_spec.rb

@@ -0,0 +1,38 @@
+require "rails_helper"
+
+RSpec.describe Public::BillingHelper, type: :helper do
+  before { load Rails.root.join("db/seeds/plans.rb") }
+
+  let(:premium_light) { Plan["premium_light"] }
+  let(:premium_full) { Plan["premium_full"] }
+  let(:free_plan) { Plan["free"] }
+
+  it "segna il piano corrente" do
+    action = helper.plan_billing_action(
+      current_slug: "premium_light",
+      target_plan: premium_light,
+      stripe_subscription_active: true
+    )
+    expect(action[:kind]).to eq(:current)
+  end
+
+  it "propone attivazione da free" do
+    action = helper.plan_billing_action(
+      current_slug: "free",
+      target_plan: premium_light,
+      stripe_subscription_active: false
+    )
+    expect(action[:kind]).to eq(:checkout)
+    expect(action[:label]).to include("Attiva")
+  end
+
+  it "propone upgrade con abbonamento attivo" do
+    action = helper.plan_billing_action(
+      current_slug: "premium_light",
+      target_plan: premium_full,
+      stripe_subscription_active: true
+    )
+    expect(action[:kind]).to eq(:change)
+    expect(action[:label]).to include("Passa a")
+  end
+end