Translation in English: Translation service — Idempotency, Outbox, Circuit Breaker

Money transfer service in Go with system design patterns. Idempotency keys guarantee exactly-once on retries through SELECT FOR UPDATE with response caching. Business data and events are written in a single serializable transaction via Transactional Outbox — relay publishes through SKIP LOCKED. Circuit breaker protects against cascading failures. Token bucket rate limiter on the client. Prometheus metrics, account API, graceful shutdown. 18 unit tests.