feat: implement TradeModal for buying and selling coins with validation and transaction handling
feat: create server-side trade API for executing buy/sell transactions and updating user balances
feat: add transactions API to fetch user transaction history
feat: implement portfolio page to display user's holdings and recent transactions
feat: create user image retrieval API endpoint
feat: enhance coin page with dynamic data fetching and improved UI
feat: implement coin creation form with validation and submission logic
feat: add user settings page with profile update functionality
