- Remove unused stdexec dependency
- Fix dangling cv::Mat references and swapped dimensions in image/matrix factories
- Add CameraCalib, StereoCalibrationRPC, ImagePairRPC DTOs with nlohmann serialization
- Implement get-stereo-calibration and get-image-pair RPC handlers with deterministic mock data
- Extend RpcClient with typed getters and params-bearing call overload
- Restructure API.md with full JSON schemas and conventions
- 13 unit and integration tests for serialization
TG-3 #in-progress
TG-7 #ready-for-test
