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/models/billing/invoice_spec.rb

@@ -0,0 +1,27 @@
+require "rails_helper"
+
+RSpec.describe Billing::Invoice do
+  let(:club) { Club.create!(name: "Invoice Club", sport: "volleyball", primary_color: "#e53935", secondary_color: "#ffffff") }
+
+  it "richiede PDF per fatture emesse" do
+    invoice = club.billing_invoices.build(
+      number: "2026/001",
+      issued_on: Date.current,
+      amount_cents: 4000,
+      status: "issued"
+    )
+    expect(invoice).not_to be_valid
+    expect(invoice.errors[:pdf]).to be_present
+  end
+
+  it "accetta bozza senza PDF" do
+    invoice = club.billing_invoices.create!(
+      number: "2026/002",
+      issued_on: Date.current,
+      amount_cents: 4000,
+      status: "draft"
+    )
+    expect(invoice).to be_persisted
+    expect(invoice.downloadable?).to be false
+  end
+end