flow-mn/flow ? reverse-engineered prompt

Build me a beautiful Flutter expense tracker app called Flow that helps people keep track of their money without any fuss.

I want it to work fully offline, feel simple and polished, and let users add expenses and income across unlimited accounts and currencies. It should support categories, tags, optional file attachments, and location tagging, plus let people reflect on their spending with useful summaries or insights. Please include backup and restore features so data can be saved as ZIP or JSON, exported as CSV and PDF, and automatically backed up to iCloud when possible. It should be free, open source, and not use trackers or analytics.

If you can, also add a way to create transactions through app links or custom URI actions, and make sure the app works well on mobile and desktop. Look up current Flutter docs online if you need to.