The 45-Channel Hypothesis in ISC 1.0: A Phenomenological Framework Linking α, S₈, and Discrete Decoherence

Fifth paper in the ISC 1.0 series. We present the 45-channel hypothesis as a phenomenological framework connecting the fine structure constant to cosmological observables. Observing α⁻¹ = 3N+2 with N = 45.011999..., we postulate N=45 discrete decoherence channels. Adopting the ansatz that D5→D3 projection loses 12 gauge degrees of freedom with probability α each, unitarity gives f = (1-12α)^{1/45} = 0.997966 per channel. This predicts S₈ = 0.832 × (1-12α) = 0.759 with zero free parameters, resolving the S₈ tension from 2.7σ to 0.06σ. The model predicts 45 log-periodic suppressions in P(k) with Δln(k) = 0.084, falsifiable by Euclid. Full QFT derivation from Cl(4,1) left for v2.