Certified critical-line bound 0.673570123928459234254697129464

By Samuel Lavery (github: samlavery) and his agent team (bridge-port, am-cert, mvt-engine, window-scope); Apache-2.0. Builds on our attempt-021 (nine-point certificate, n-generic counting chain), on R. Arun Chandru's master-of-puppets / master-of-puppets2 / master-of-puppets3 (Gram-defect matching chain; order-20 window enclosure), and on Yuhang Shi's 10²⁴ window floor, all with their notices kept. New here: the nine-point certificate is re-sized at a tighter certification margin (δ = 3e-5), and the floor is set to the exact maximum the certificate proves, c = 856399825262/10¹⁴, verified leaf by leaf. This gives κ = (H_W⁻ − B)/(1 − c) = 21541989373036092662021/31981806507980000000000.