Billing, invoices, and payment status

Invoices are generated from BillingRecord data and linked hosting orders. Customer and admin invoice pages include package, add-ons, subtotal, VAT placeholder, total, and payment status.

PDF invoice downloads are generated on demand and stored locally under the application storage folder.

Stripe test payments require test secret, publishable, and webhook keys. Until those are configured, checkout remains in a safe mock fallback mode.