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/app/helpers/public/billing_helper.rb

@@ -0,0 +1,29 @@
+module Public
+  module BillingHelper
+    def plan_billing_action(current_slug:, target_plan:, stripe_subscription_active:)
+      return { kind: :current, label: "Piano attuale" } if current_slug == target_plan.slug
+
+      if target_plan.slug == "free"
+        return { kind: :contact, label: "Contatta il supporto per downgrade." }
+      end
+
+      unless MatchLiveTv.stripe_enabled?
+        return { kind: :disabled, label: "Stripe non configurato" }
+      end
+
+      if current_slug == "free" || !stripe_subscription_active
+        return { kind: :checkout, label: "Attiva #{target_plan.name}" }
+      end
+
+      if Plan.tier(target_plan.slug) > Plan.tier(current_slug)
+        { kind: :change, label: "Passa a #{target_plan.name}" }
+      else
+        { kind: :change, label: "Passa a #{target_plan.name}" }
+      end
+    end
+
+    def stripe_subscription_active?(subscription)
+      subscription&.stripe_subscription_id.present? && subscription.active?
+    end
+  end
+end