X(2370) as a Pseudoscalar Glueball Candidate: A TDE Pure-Gauge Analysis of the BESIII 0 −+ Resonance

This addendum extends the TDE v19.0 Dynamic Resonance Map to a pure-gauge / glueball sector, motivated by recent BESIII results on X(2370) as a J^PC = 0^-+ pseudoscalar glueball candidate. In the TDE lattice, X(2370) is tested as a resonance with no ordinary valence-quark flavor assignment, described instead by a pure-gauge operator gate combined with flavor-singlet, OZI-suppression and shadow/gauge-action constraints. The mass test identifies a compact TDE node for the 2376.3 MeV solution: (A,B,C) = (5,1,7). This gives M_TDE = 2375.787 MeV, with an absolute deviation of approximately 0.513 MeV. For the 2359 MeV combined BESIII parameter choice, the same TDE trunk 5E0 + E1 is recovered with C approximately 0 to 0.5, again giving sub-MeV agreement. The radiative-production balance J/psi -> gamma + X(2370) also closes at the sub-MeV level in the TDE Q-value test. The addendum then applies a pure-gauge operator gate to the observed and suppressed decay patterns. In the MTDE-17 implementation, flavor-singlet-compatible channels retain nearly all transition pressure, while K*(892) Kbar and radiative gamma omega / gamma phi channels are strongly suppressed after the pure-gauge/OZI/shadow gate. This reproduces the qualitative pattern emphasized in the BESIII interpretation: radiative J/psi production, J^PC = 0^-+, flavor-singlet behavior and suppression of selected non-singlet or radiative-vector channels. The result is presented as a rapid reproducible computational addendum, not as an experimental discovery claim. Its purpose is to show that the X(2370) pseudoscalar glueball candidate is consistently represented in TDE as a pure-gauge resonance node, and that the TDE v19 operator-gate formalism can be extended from ordinary hadron decay dynamics to gluonic degrees of freedom.