📝 docs(instructions): update response language requirement

- change "Always response in Chinese" to "必须用中文回答" for clarity and consistency with other instructions

CLAUDE.md

@@ -11,4 +11,4 @@
 - use pnpm
 - 数据库在同一容器组的另一个容器中，需要运行 psql -h 127.0.0.1 -U postgres 来访问
 - bmad-core dir is in .bmad-core
-- Always response in Chinese
+- 必须用中文回答