Sync Engine with development main

[mlgorithm]

This syncs TreeWidzard-Engine with the current development main tree while preserving both histories.

The branch contains a two-parent merge commit:

• parent 1: current Engine cleanup history
• parent 2: development main
• final tree: exactly matches development main

Also keeps the generated-artifact cleanup:

• no tracked build artifacts
• no CLUSTERREADME.md
• generated outputs routed under out/

Local verification:

• CMake configure/build with tests enabled passed
• CTest passed: 435/435
• README.md and examples.md runnable examples passed