- split settings module into per-struct files
- add DatabaseSettings with default in-memory SQLite path
- implement RelayApi struct with GET /relays and POST
/relays/{id}/toggle
- wire create_relay_controller and create_label_repository into
Application::build() with mock/real selection via cfg!(test) || CI
- register RelayApi in OpenApiService alongside existing APIs
- Add Relay entity with constructors and business logic methods
- Add RelayDto for API responses with From<Relay> conversion
- Add ApiError with ResponseError trait for unified error handling
- Add dependency injection tests for mock infrastructure in test mode
Convert project from single backend to monorepo structure with separate
frontend (Vue 3 + TypeScript + Vite) and backend directories. Updates
all configuration files and build system to support both workspaces.
Ref: T007 (specs/001-modbus-relay-control)
