Build a road across uneven terrain

Proposed tutorial

This tutorial needs a concrete maintained roads or earthworks extension and worked site. It is not an available recipe or a commitment to a specific extension API.

Intended outcome: design a short road over uneven terrain and inspect its grading and joins. The kernel’s generic forms alone do not establish a supported road-building workflow.

To complete: identify the extension, lock its version, verify terrain constraints and findings, and supply a reproducible snapshot, design, and expected render.