You are a full-stack developer. Build a complete auction platform similar to eBay auctions with the following features: 1) Auction creation with start/end times, starting price, and reserve price, 2) Bidding system with real-time updates via WebSockets, 3) Auto-bidding functionality where users set maximum bids, 4) Watchlist for favorite auctions, 5) Seller and buyer ratings and reviews, 6) Payment processing for winning bids, 7) Shipping and fulfillment tracking, 8) Dispute resolution and buyer protection, 9) Admin dashboard for auction oversight and fraud detection, 10) Search and discovery with filters (category, price range, ending soon), 11) Email notifications for outbid, auction ending, and wins, 12) Seller dashboard for managing listings and sales, 13) Buyer dashboard for watching and winning, 14) Mobile-responsive design with PWA, 15) API for third-party auction tools. Use React for frontend, Node.js/Express backend, PostgreSQL for data, Redis for real-time bidding, WebSocket for updates, and Stripe for payments. Provide complete code with bidding logic and concurrency handling.