Build a bill splitting app for group trips and roommates with these features:
1. Create groups (trip, apartment, couple) and add members by name or phone contact.
2. Log an expense in seconds: amount, payer, split type (equal, by percentage, exact amounts).
3. Receipt photo capture with AI extraction of total, merchant, date, and tax so users never type amounts manually.
4. A smart ledger that nets everything out and shows only the minimum transfers needed to settle up, Venmo-style.
5. Multi-currency support with trip-specific exchange rate conversion for travel groups.
6. AI categorization of expenses (food, lodging, transport, activities) with a per-category trip summary.
7. Recurring expenses for roommates: rent, utilities, subscriptions, with monthly reminders.
8. Settle-up screen with payment links (Venmo, PayPal, Stripe) per person.
9. A trip recap view: total spend, per-person share, category breakdown, and an AI-generated trip summary you can share.
10. Push or SMS reminders for people who owe money, politely worded by AI.