chore(workflow): 工作流相关代码中文文案全部英文化

源码（src/workflow/ + packages/workflow-engine/src/）的中文注释、
用户可见错误消息、字符串字面量；测试文件的标题与注释；同步 6 条
硬编码断言到英文化后的错误消息。

Co-Authored-By: glm-5.2 <zai-org@claude-code-best.win>

packages/workflow-engine/src/engine/structuredOutput.ts

@@ -3,8 +3,8 @@ import { Ajv, type ValidateFunction } from 'ajv'
 const cache = new WeakMap<object, ValidateFunction>()
 
 /**
- * 用 JSON Schema 校验 agent 输出（Ajv，编译结果按 schema 对象缓存）。
- * 引擎对 adapter 返回的 schema 结果做二次校验，并用于测试。
+ * Validate agent output against a JSON Schema (Ajv, compilation result cached by schema object).
+ * The engine performs secondary validation on the schema result returned by the adapter, and uses it for tests.
  */
 export function validateAgainstSchema(
   value: unknown,