DCRP96 / X72R79: Circulation Young Profile and Nematic Lock

Following DCRP95's sign-coherent SGS phase-slip conveyor C_slip, this round tests the original hypothesis that sign-coherent circulation slip forces a nonzero barycenter shift in the increasing Young profile, and the answer is no (the Barycenter NO-GO): the SGS circulation functional is quadratic in the velocity increment, so a centered, sign-symmetric Young measure (such as (δ_{e1}+δ_{-e1})/2) can still carry a nonzero circulation flux. The true rigidity variable is the deviatoric second moment: it proves that sign-coherent phase slip instead forces a trace-free deviatoric/nematic covariance lock, and that circulation reset and positive SGS work are two linear projections of the same deviatoric covariance, so pure covariance algebra cannot rule out both holding at once. The conclusion leaves the next round to determine whether this narrowed dual-lock PSD cone is compatible with rank-two carrier geometry and X72 dynamics.