Implements CorsSettings struct with validation and deserialization support
for configuring Cross-Origin Resource Sharing in the application settings.
Ref: T010 (specs/001-modbus-relay-control)
- Add domain types: RelayId newtype and RepositoryError enum
- Implement SqliteRelayLabelRepository with in-memory test support
- Create relay_labels migration with SQLx compile-time verification
- Add comprehensive integration test suite (266 lines)
Ref: T006 (specs/001-modbus-relay-control)
Switch from Modbus RTU over TCP to native Modbus TCP based on hardware
testing. Uses standard MBAP header (no CRC16), port 502, and TCP-only
tokio-modbus feature for simpler implementation.
Updated: Cargo.toml, plan.md, research.md, tasks.md
Adds tokio-modbus 0.17.0 for Modbus RTU over TCP communication,
sqlx with runtime-tokio and sqlite features for async database operations,
mockall 0.13 for trait mocking in tests, and async-trait 0.1 for async trait support.
Ref: T001 (specs/001-modbus-relay-control)
