the model is the agent, the code is the harness

Comprehensive rewrite of all three READMEs (EN/ZH/JA) and the agent
philosophy reference. Core narrative: agent = trained model, code =
harness (the environment built for the agent). Added historical proof
(DQN, OpenAI Five, AlphaStar, Tencent Jueyu), "Why Claude Code" as
a masterclass in harness engineering, harness engineer role definition,
universe vision, and consistent harness terminology throughout.

Author: CrazyBoyM