Open Payment Link (Hosted)

Customer-facing hosted pay page. No merchant auth — the token query param IS the credential (from the shared /pay/{token} URL). Returns the CheckoutSessionViewResponse wrapper: { session, payment_methods, saved_payment_methods } — the SAME shape /onetime/checkout returns, so the same hosted UI renders it.

🔒 saved_payment_methods is always [] on a payment link (a shared bearer link must never expose or charge the target customer's saved cards) — the customer enters a NEW card. Rate limit: 60/min per IP. A canceled / expired / already-paid link → 409.