A Noise-Invariant Determinism Theorem for Multi-Base Post-Processing in Shor's Order Finding (v0.3.0: closed-form σ-curve framework + §3.6 self-correction)

v0.3.0 of the multi-base post-processing analysis of Shor's order finding. The original five theorems (v0.2.1, DOI 10.5281/zenodo.20681847) are retained unchanged: (1) noise-invariant determinism, (2) logarithmic coverage time, (3) exact noise scaling 1/g_M(η), (4) conditional compatibility with Regev's 2023 multi-base framework, and (5) a hybrid (C)+Regev b-trick factoring algorithm with closed-form bound matching N=437 empirical mean within 4%. New in v0.3.0: §3.6 of v0.2.1 is *self-corrected*. The previously claimed 'boundary-flip + universal direction stochasticity + plateau/overload' framework is shown to be the finite-trial expression of a single closed form p(σ) = ρ + (p_0 - ρ)·exp(-σ²) derived from the standard phase-noise dephasing of the FFT. The closed form is verified across five algorithm classes — Grover (R²=0.88), Shor pure (0.95), QPE isolated (0.96), Simon (0.99), Hybrid (C)+b-trick (paper §3.6 setup, 0.91). Positioning: analytical complement to Yang-Markidis (arXiv:2605.16074, ICS Workshops '26), whose empirical recoverability model (1-ε)·P_s + ε·distractors has the same structural form; we provide the analytical foundation ε = 1 - exp(-σ²). Implication: SR-based factoring acceleration is precluded by a closed-form bound on |ΔK|. v0.3.0 retracts the 'boundary flip' lexicon as a distinct mechanism; all raw measurement data and theorems 1-5 are retained.