Add private payment-confirmation form to sci-fi checkout

[Copilot]

The sci-fi checkout needed a buyer-facing transfer confirmation step for manual QR/bank payments without ever exposing the recipient email in static client assets. This change adds a Hungarian confirmation form, keeps delivery disabled until a public submit endpoint is configured, and documents the privacy-preserving integration point.

• Checkout flow

  • Added a second-step payment confirmation form inside docs/scifi-ui for transfer notifications.
  • Prefills order/reference, selected plan, cycle, currency, and amount from the checkout state.
  • Keeps the existing demo card flow intact while making transfer selection drive the confirmation experience.

• Privacy boundary

  • Introduced a single isolated client config point via formatx-payment-confirmation-endpoint.
  • Submission is disabled by default when no public endpoint URL is configured.
  • Removed any implication that the static site can directly send private email; recipient address stays in Formspree/backend config only.

• Buyer-facing UX

  • Added Hungarian fields for:
    • order/reference ID
    • selected plan/currency/amount
    • payer name
    • buyer email
    • transfer reference
    • optional message
    • consent
  • Added clear disabled-state copy when the form is not connected.
  • Preserved keyboard usability and responsive layout across themes, including ?theme=holo.

• Docs

  • Added concise setup notes for wiring the public endpoint to Formspree or a serverless handler while keeping the recipient email private.
  • Expanded the sci-fi UI manual verification notes for the confirmation form.

<meta
  name="formatx-payment-confirmation-endpoint"
  content="https://formspree.io/f/your-public-form-id"
>

const paymentConfirmationMeta = document.querySelector(
  'meta[name="formatx-payment-confirmation-endpoint"]'
);
const paymentConfirmationEndpoint = paymentConfirmationMeta?.content?.trim() || '';