Restaurant Menu System Functionality Update

Add authentication system and admin dashboard with order management

• Implement customer login/signup with secure password hashing and session management
• Create admin portal with separate authentication and role-based access
• Add order management tab with real-time status tracking (pending -> preparing -> ready -> completed)
• Implement 5-second polling for live order status updates across admin and customer views
• Add admin dashboard with 4 tabs: Orders, Order Management, Menu Management, Admin Management
• Create database schema for admins table and add order_status column to orders table
• Build backend routes for order operations and admin authentication
• Add admin signup endpoint allowing existing admins to create new admin accounts
• Implement secure admin credentials with email validation and password requirements
• Add status badge styling with color-coded order states
• Improve UI/UX with consistent theme across authentication pages and dashboards
• Add logout functionality for both customer and admin accounts