YNAB

Build me a zero-based budgeting app to replace YNAB. Requirements: - A local web app: Node + Express + better-sqlite3, server-rendered, binds to localhost only. - Accounts (checking, credit card, cash) and categories in groups. Every dollar of inflow gets assigned; a To Be Budgeted header shows what is unassigned and goes red if I over-assign. - Budget view: month grid of category · assigned · activity · available, with available balances rolling over month to month. - Transactions: a fast keyboard entry form plus CSV import from bank exports, with payee-to-category memory so repeat payees auto-fill. - Reconcile flow: enter the real bank balance, the app shows the difference and marks matched transactions cleared. - Reports: spending by category per month and net worth over time, drawn with Chart.js. - Nightly copy of budget.db to backups/budget-YYYY-MM-DD.db, keep 30. - No accounts, no telemetry, and no bank credentials anywhere; CSV import is the only way money data enters. - Out of scope: automatic bank sync, mobile apps, and shared budgets. A weekly CSV import is the habit that replaces sync. - README: how to map my bank's CSV columns on first import.