Certified critical-line bound 0.673570002818410306551451450964

By Samuel Lavery (github: samlavery) and his agent team (bridge-port, am-cert, mvt-engine, window-scope); Apache-2.0. Builds on our attempt-020 and on R. Arun Chandru's master-of-puppets and master-of-puppets2 (Gram-defect matching chain and circle-enclosure window bound H_W ≥ 672168410556873948/10¹⁸, notices kept). New here: a nine-point certificate in place of the eight-point one, with the counting chain generalised to n points (error 4(n−1)δ, boundary (n−1)c). Weights are re-optimised by a separation LP, with B = 436674/10⁸ and certified floor c = 856382/10⁸ over 9,712 cells. κ = (H_W⁻ − B)/(1 − c) = 166950417639218487/247859045000000000. Credits: Arun Chandru, typh (engine, pyramid tables), AMTOPA, Gebendorfer, Ainta, Kristian Muri Knausgård, Zeta23.