Density-Gated Tachyonic Gravity (Alves v4): Phase Transition at a=0.6 and Auto-Flagged LIGO Precursors

This is v4 of the Density-Gated Tachyonic Gravity theory by Tiago Alves (ORCID 0009-0004-8347-1373). This version fixes the critical phase transition at scale factor a=0.6. Gravity is attractive when density is above critical (a<0.6) and repulsive when below (a>0.6), producing accelerated expansion without Dark Energy. Key results in this version: 1. Auto-flagged AI detection of ∼9.8 sigma LIGO precursor anomaly. 2. Gravitational lensing suppression. 3. Coherent flow of galaxies. 4. Mathematical proof that density gating prevents gravitational singularities. All figures are openly licensed CC-BY 4.0.