v5.1: clean architecture

v5.1 "clean architecture": the same three tools as one package with one command, a versioned web API, training jobs you can follow and cancel, and the documentation. Project version: 5.1.0.

Test result: 803 automated tests pass; ruff, mypy and pip-audit are clean. A cancelled training on the full NSL-KDD files stops, frees its memory and keeps nothing; the progress bar, Cancel and a reload during training work; the whole flow works with the keyboard only; a fresh install on Windows passes every menu path (gate record, every check mapped to its tests in the audit). The web and the CLI label the full KDDTest+ file the same, byte for byte. The ML report on the v5.1 code gives the 5.0 numbers: all 1,246 values equal. Windows 10 Enterprise LTSC 2021, Python 3.14.3 (an install on Python 3.11.0 checked too), scikit-learn 1.8.0.

Everything that changed, with the known limits: CHANGELOG.

An older version, kept for the record: the latest is v5.4.