MonetaryAmount

Represents a monetary value with its associated currency, ensuring that amounts are always paired with their currency context to prevent errors and ambiguity. This entity implements the Money pattern from domain-driven design, treating amount and currency as an inseparable pair. It supports financial calculations, multi-currency operations, currency conversion tracking, and proper monetary value handling across invoicing, payments, pricing, subscriptions, and financial transactions. The entity prevents common financial bugs such as adding amounts in different currencies, comparing incompatible monetary values, or losing currency context. It serves as the foundation for all financial operations in e-commerce, accounting, billing, and enterprise systems.