Fix & Complete Stripe Payment Flow for Mushroom E-commerce Site (Next.js + NestJS)

We run an online shop selling culinary and medicinal mushrooms — fresh, dried, and grow kits. The site is built and the catalog works; the checkout is where we need help. Some of it is half-finished, some of it is behaving incorrectly in production. Scope of work Complete our Stripe integration using Stripe Checkout (hosted) or Payment Element, whichever you'd recommend for our case Fix the order lifecycle so state transitions are reliable: pending → paid → fulfilled → refunded Stripe webhook handling (checkout.session.completed, payment_intent.succeeded, payment_intent.payment_failed, charge.refunded) with signature verification and idempotency, so a retried event never double-charges or creates a duplicate order Resolve orders stuck in "pending" when a webhook never arrives — reconciliation job or a manual recovery path in admin Refund and partial-refund flow triggered from the admin panel via the Stripe API Order confirmation email with receipt, sent once and only once per paid order Audit trail on payment events so we can trace any disputed transaction back to a Stripe object Our stack Frontend: Next.js (App Router), TypeScript Backend: NestJS + GraphQL Database: PostgreSQL (Supabase) Hosting: AWS Payments: Stripe What we're looking for Production Stripe experience end to end — please describe a project where you shipped it, not just test-mode work Comfortable debugging webhook-driven state machines, not just the happy path Able to write a short handover doc covering the payment states and how to recover a failed order To apply Reply with: (1) a Stripe integration you shipped to production and what it handled, (2) how you'd handle a webhook that arrives twice for the same order, (3) your hourly rate and weekly availability.