V.T44 — Chandrasekhar limit

The Chandrasekhar threshold n_Ch exists and is unique. The critical mass M_Ch = n_Ch * m_n = T_A^max / ((1-iota_tau) * m_n) approximately equals 1.4 M_sun, matching the observed M_Ch = 1.44 M_sun within the precision of the tau-effective derivation.