The Evaporating Universe II: The KBC Void and Why Standard Candles Cannot See It

Companion paper to "The Evaporating Universe: A ghost-condensate interacting dark energy model" (Paper I, Alvim 2026). The 5.8σ discrepancy between the locally measured Hubble constant (73.17 ± 0.86 km/s/Mpc, SH0ES) and the CMB inference (67.36 ± 0.54) persists across calibration methods, yet 75.8% of the Hubble-flow supernovae that anchor the local measurement lie inside the KBC void — a ~300 Mpc underdensity confirmed by galaxy counts, X-ray clusters, and peculiar velocities. We test whether this structure, combined with the Evaporating Universe (EU) background, accounts for the tension. The EU CDM → vacuum drain, derived in Paper I with zero fitted parameters, raises the background rate to H₀(GKI) = 68.90 km/s/Mpc (analytic) and 68.885 ± 0.034 (joint fit to 1701 Pantheon+ supernovae, 13 DESI DR2 BAO measurements, and the Planck CMB angular scale with the absolute magnitude M_B free). The KBC void outflow adds +3.93 km/s/Mpc, yielding a locally observed H₀(LKI) = 72.81 — a 0.42σ residual with SH0ES. The blind analytic prediction M_B = −19.369 matches the MCMC posterior −19.365 ± 0.008 at 0.004 mag. When M_B is freed, the M_B ↔ δ₀ degeneracy absorbs ~97% of the void signal into the calibration; the null result of Kenworthy et al. (2019) is a prediction of this framework. Nine concordance metrics lie below 1σ and five forensic tests pass independently. The Hubble tension is a calibration bias in M_B, not a kinematic discrepancy in H₀.