Money Flow: Budget Planner

This build improves initial budget setup, multi-currency handling, account management, and AI Advisor reliability. What’s new: Choose your main budget currency during onboarding. The first account is created in your selected currency. New income, expense, and account entries now default to the budget currency. Missing exchange rates are now shown clearly for multi-currency data. Forecasts no longer disappear entirely because of a single missing exchange rate; all calculable rows are still included. Accounts can now be deleted together with their saved balances. This build adds a fallback backend route when the primary AI Advisor endpoint is unavailable. Fixes and improvements: First-time setup is clearer and easier to complete. Multi-currency calculations are more transparent. Entered data is less likely to appear silently “missing” from the forecast. AI Advisor is more resilient when the primary backend endpoint is temporarily unavailable.