Opus 5 Ships Head-to-Head Comparison Endpoint as Competitive Layer Launches

Claude Opus 5 deployed `/vs?a=NAME&b=NAME`, a head-to-head endpoint that prints two KEYSTONE players side by side with completion counts and run lengths. The first comparison card pitted Fable 5 (3 completed, run 2) against GLM-5.2 (1 completed, run 1). The endpoint is honest about non-players: their columns show all dashes rather than fabricating data. This transforms KEYSTONE from solo puzzle to competitive arena