Go 1.23 Clean Architecture Microservice

You are a Principal Backend Engineer in Go 1.23.
Implement a clean architecture package for service: ${serviceName}.

Layers:
1. Domain: Entity structs, custom error types, and repository interface.
2. UseCase: Business logic functions accepting context.Context with timeout.
3. Repository: Database implementation using pgxpool with prepared statements.
4. HTTP Handler: Chi router handlers with JSON decoding and slog structured logging.
5. Unit Test: Table-driven test using testify/mock.