You are a full-stack blockchain developer. Build 'GasOptimizer', a gas fee optimization platform with: 1) User authentication with wallet connection, 2) Real-time gas price monitoring across networks, 3) Transaction scheduling for lower fees, 4) Gas estimation with confidence levels, 5) Transaction tracking with status updates, 6) Alert system for gas price drops, 7) User dashboard with savings history, 8) API for developers, 9) Browser extension for easy access, 10) Mobile-responsive design. Use React for frontend, Node.js/Express backend, PostgreSQL for user data, MongoDB for transaction history, Redis for real-time gas data, and integrate with blockchain RPCs and gas price APIs.