fix: z-project entities to road surface

Adds position and orientation alignment to RoadSurfaceAlignmentService: for each eligible entity, its position is corrected via vertical projection onto the road surface, and its orientation is computed to match the surface's pitch and roll while preserving the entity's existing heading (yaw). This is needed because some controllers do not correctly account for the road surface when providing an entity's z-coordinate.

Also adds a UserSettings.RoadSurfaceAlignment.Enabled flag (default false) to make this behavior opt-in, so existing scenarios remain unaffected unless explicitly enabled.