betterversionofpuja/relocation-companion — reverse-engineered prompt

Build me a full stack web app called Relocation Companion that helps people compare cities side by side before deciding where to move. I want a clean, modern, mobile friendly interface where someone can pick two or more cities and see things like affordability, cost of living, rent, internet costs, salaries, food and transport index, quality of life, healthcare, safety, and pollution or environment scores in an easy to understand way. Use the 2024 and 2025 world cost of living and quality of life dataset as the source, and make it clear the data is educational and not live.

Please include sign up and login, a user profile page, and a way for users to save their favorite city comparisons and come back to them later. The app should feel polished and smooth, with simple navigation and helpful visuals for comparing cities quickly. I also want a backend API with a database for users and saved comparisons. If you need anything, look up current docs online and just wire up a complete working version end to end.