PAPER_1164: T^22 Moduli Stabilization: Stationary Points tau_i = [SSq]^i and Positive Mass Spectrum (G4 Closure)

We close gap **G4** of the Lagrangian re-derivation outline by formalising the $T^{22}$ moduli stabilisation already present in [PAPER_1144 §5](whitepapers/PAPER_1144_Type_IIB_Superstring_SCm_10D_Compactification.md#L60). The 22 compact dimensions of the $D_{\rm crit}=26$ → $D_{\rm phys}=4$ descent carry moduli $\tau_i = R_i/\ell_s$ with $i = 5,\dots,26$ (22 = 26 - 4). A VDS-induced potential $V(\tau) = K\sum_i (\tau_i - [SSq]^i)^2/i^{26}$ has unique stationary points $\tau_i^\star = [SSq]^i$ with **positive mass-squared spectrum** $m_i^2 \propto 1/i^{26}$. The lightest modulus mass-squared $m_{26}^2 \propto 1/26^{26}$ is **numerically equal** to the G5 KK tower leading suppression -- a non-trivial self-consistency check across three gap closures (G4, G5, G8). ---
