[Refactor/Chore] Add preflight workflow validation and actionable diagnostics for missing variable references / unreachable paths
![[Refactor/Chore] Add preflight workflow validation and actionable diagnostics for missing variable references / unreachable paths](https://www.chat-gpts.plus/wp-content/uploads/2026/09/34358-5d0ee5cc-768x403.jpg)
当 Dify 的 Advanced Workflow 存在变量引用缺失、条件/并行分支输出未实际产生、图结构不可达等定义问题时,界面可能一直停在 cacheing variables ,SSE 返回 internal_server_error ,随后前端还会对一个从未成功生成的答案发起 sugges








