Guarda un gasto manual, no realiza pagos. amount_cents entero (12345 = 123,45).

Requiere credenciales del negocio. El servidor determina autor, origen y sucursal.
No es idempotente: ante una respuesta incierta consulta gastos antes de repetir.

Integration access is restricted to the credential's location. Pagination, monetary units and response envelopes are endpoint-specific; use the schema below. Do not assume that POST/PATCH requests are safe to retry after a timeout.