V.P09 — CnuB mass constraint

The CnuB echo surface constrains the total neutrino mass via the neutrino-to-matter density ratio: sum m_nu <= 0.12 eV (cosmological bound). The tau-prediction sum m_nu ~ 58 meV (from m_nu ~ m_e * iota_tau^15) is consistent with current bounds and testable by KATRIN and next-generation surveys.