Stripe Integration Fix for Lovable and Supabase App

I have a SaaS platform built with Lovable and Supabase and the Stripe integration is half done. Checkout sessions were set up but payments are failing in live mode, webhooks are not verified, and subscription status is not syncing back to the Supabase database. Users can pay but their accounts do not unlock. I need a developer with real Stripe experience to troubleshoot and complete the integration: fix the checkout flow for subscriptions and one time payments, set up and verify webhooks, fix product and price ID issues, connect payment status to user entitlements in Supabase, and make sure everything works correctly in both test and live modes. If you have done Stripe Connect for marketplace payouts before, that is a plus since we may add it later. Please reply with your relevant Stripe experience and one example of a payment integration you completed. I need someone who can work independently and start urgently.