Introduced an admin_required check for all admin routes using Flask-Login's current_user. Updated the FoodItems model to use per-100g nutritional fields and removed unit relationships. Seed script now creates both admin and regular user accounts.
Add base Flask application with user authentication, SQLAlchemy models for users, units, and food items, admin blueprint, and basic templates. Includes database migration setup, login form, and seed script for initial user creation.
