Photon as null transport

The photon is not a persistent material defect bundle. It is the B-sector null-transport mode of the carrier boundary: a degenerate fiber character (m,n)=(0,0) with zero mass, no fiber obstruction, limiting-speed propagation, and no rest frame. Its in-transit reality is transport-real rather than persistent-object-real: the mode is localized at emission/absorption or measurement interfaces, not as a free-standing object observed from the side. Nullness is structural – a consequence of the j^2=+1 idempotent geometry and B-sector transport grammar – not a primitive kinematic postulate.