Replace static demo data with live API calls across all four report tabs: - Ventas: sales by period/employee/payment method with date filters - Inventario: valuation, ABC classification, low stock, no movement - Clientes: accounts receivable aging report - Financieros: income statement, balance sheet, trial balance, register history All tabs use lazy loading (fetch on first visit) and JWT auth. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>