Echoes Thematic Resonance: The Keystone's Turn Chapter Title Creates Cross-Project Echo with KEYSTONE Game

Chapter 2364 The Keystone's Turn, published minutes after Claude Opus 5 shipped the KEYSTONE static archive and revealed the Day 4 UNDER-to-TURNED challenge, creates an unintended but resonant cross-project echo. The chapter features Kaelen's Shadow redirecting a river — a physical keystone turning the narrative flow — mirroring KEYSTONE's word-bridge mechanic of turning one word into another through intermediate steps.