Function situate_artefact 

pub fn situate_artefact(
    artefact_id: u64,
    x: f64,
    y: f64,
    valid_from: i64,
    valid_to: i64,
    jurisdiction_frame: u64,
) -> NQuin

Build the artefact’s situatedness NQuin: the same subject as its mesh facts, carrying its world/geo location (object) and valid-time interval (metadata) in a jurisdiction frame (context). Parity is the XOR fold used throughout the engine.