Fix: guest club & form payments now actually confirm after a successful charge.
A guest could pay successfully (card charged) and see the "registered" page, but the registration could stay on "payment pending" with no transaction recorded — because the webhook that confirms the payment failed when the school had a connected Stripe account. Guest/form charges are destination charges that live on the platform, but the confirmation handler was re-reading the Checkout Session on the connected account, where it doesn't exist, and aborting. Fixed: it now reads in platform context, so the registration flips to confirmed and the payment is recorded.