Invoices: extract data and review

• Convert invoices into structured data.
• Detect missing or inconsistent fields.
• Prepare a CSV that a person can review.

Devuelve SOLO JSON válido con esta estructura:
{
  "numero_factura": "",
  "fecha": "",
  "emisor": "",
  "nif_emisor": "",
  "cliente": "",
  "base_imponible": 0,
  "iva": 0,
  "total": 0,
  "vencimiento": "",
  "alertas": []
}

Si falta un dato, deja el campo vacío y añade una alerta.

Useful automatic checks

• Total = base + VAT - withholdings, if applicable.
• Date and due date have a consistent format.
• NIF/CIF is not empty.
• Supplier already exists or is marked as new.
• High amounts require manual review.