Build an expense tracker with charts

• A form adds an expense with amount, category, date and note; amounts must be positive numbers with at most two decimals
• Expenses can be edited and deleted, and the list is sorted by date and shows a formatted currency amount (Intl.NumberFormat)
• Filters by category, month and text search update both the list and the totals
• Summary shows total spend for the selected month and a breakdown by category, with a chart (bar or pie) and a monthly trend chart for the last six months
• Data persists in localStorage (guarded parse and write) and survives reload; invalid stored data does not crash the app
• Money is stored as integer minor units (cents) to avoid floating-point errors

Only after every requirement works.

• Monthly budget per category with warnings when exceeded
• Export to CSV and import from CSV
• Recurring expenses