I have a partially built e-commerce site for pet accessories running on the MERN stack and I need it taken all the way to a polished, production-ready launch. The current codebase works, but bugs are scattered across the entire website—frontend layout quirks, backend logic hiccups, and the checkout flow stalls unexpectedly. Your role is to stabilise what’s there, complete any missing commerce modules, and hand back a fast, secure and responsive store: • Resolve every blocking bug across React, Node, Express and MongoDB layers • Finish core shopping features (catalog browsing, cart, secure checkout, order history) where they’re incomplete • Harden the API, clean up state management and remove console errors • Optimise for mobile and desktop, ensuring a consistent look and feel • Set up deployment (AWS, Vercel, Heroku or similar), SSL and environment variables • Provide a concise hand-over guide so I can maintain and scale the site Acceptance criteria: no runtime errors, checkout succeeds with test cards, Lighthouse performance & accessibility scores above 80, and the repository builds cleanly from a single command. If you have deep MERN expertise and enjoy squashing bugs while shipping features, I’m ready to get started right away.