IV.T93 — τ-NS Regularity on T² Fiber (C3 Defect Contractivity)

Wave 11 upgrade: C3 defect contractivity proven for T² fiber. T² Laplacian discrete spectrum λ_{m,n}=m²+n² gives exponential decay per Fourier mode. Contraction factor κ = exp(−ν·λ₁₀) < 1. Regularity unconditional within τ-admissible class on T². Scope: tau-effective for T² fiber; Clay Millennium Problem gap (T² → ℝ³) honestly acknowledged.