Preserve inherited character styles, nested child placement, history and unrelated objects while publishing the joined graph and title metadata atomically. Empty left paragraphs adopt the right text identity; left tags survive as verified in independent OneNote controls.

Validate twenty Rust joins through cold native captures. Add preservation, invalid-target, property-reference remapping and interrupted-publication checks, plus stateful split/join fuzzing. Public gate passes 186 Rust tests, 8 doctests and 130 Python tests with fmt, Clippy and builds.

Assisted-by: gpt-6-astra