Billing: fatture manuali, profilo obbligatorio e piani Stripe mensile/annuale.

Rimuove link al portale Stripe in area cliente, aggiunge flusso admin per PDF
fattura e email, blocca checkout senza dati di fatturazione, allinea prezzi
a €4,90/€39,90 e €9,90/€69,90, locale italiano e documentazione deploy.

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

backend/app/models/billing/invoice.rb

@@ -3,7 +3,7 @@ module Billing
     self.table_name = "billing_invoices"
 
     STATUSES = %w[draft issued sent cancelled].freeze
-    SOURCES = %w[aruba manual].freeze
+    SOURCES = %w[manual aruba].freeze
 
     belongs_to :club
     belongs_to :billing_payment, class_name: "Billing::Payment", optional: true
@@ -15,7 +15,8 @@ module Billing
     validates :currency, presence: true
     validates :status, inclusion: { in: STATUSES }
     validates :source, inclusion: { in: SOURCES }
-    validate :pdf_present_when_issued
+    validates :billing_payment_id, uniqueness: true, allow_nil: true
+    validate :pdf_present_when_issued, on: :issue
 
     scope :recent, -> { order(issued_on: :desc, created_at: :desc) }
 
@@ -28,16 +29,35 @@ module Billing
     end
 
     def downloadable?
-      pdf.attached?
+      pdf.attached? && status.in?(%w[issued sent])
+    end
+
+    def draft?
+      status == "draft"
+    end
+
+    def display_number
+      n = number.to_s.strip
+      cleaned = n.gsub(/\baruba[-_\s]*/i, "").strip
+      cleaned.presence || n
+    end
+
+    def display_status
+      {
+        "draft" => "In preparazione",
+        "issued" => "Emessa",
+        "sent" => "Inviata",
+        "cancelled" => "Annullata"
+      }[status] || status
     end
 
     private
 
     def pdf_present_when_issued
-      return unless status.in?(%w[issued sent])
+      return unless validation_context == :issue
       return if pdf.attached?
 
-      errors.add(:pdf, "è obbligatorio per le fatture emesse")
+      errors.add(:pdf, "è obbligatorio per emettere la fattura")
     end
   end
 end